This course is for anyone who shapes, manages or simply lives in a town or city: town planners and local council officers, architects and landscape designers, developers, sustainability and ESG staff, community organisers, and residents who want their neighbourhood to be cooler, greener and safer. No science or planning background is needed.
Module 1 shows how to see a city as an ecosystem. It covers where urban ecology came from, the difference between studying ecology in, of and for the city, how water, food, energy and materials flow through a city, how fast the world and Malaysia are urbanising, and where SDG 11 on sustainable cities stands in 2026.
Module 2 turns to green and blue infrastructure: what trees, parks, rivers, wetlands and green roofs do for a city, how ecosystem services are counted, how to plant street trees that last, what river restoration and sponge cities achieve, and who gets access to green space, from the 3-30-300 rule to the Kuala Lumpur Local Plan 2040.
Module 3 looks at the other species that share the city: which ones thrive and which disappear, how corridors and native planting keep nature connected, invasive species and conflict with macaques and crows, how drains and design shape dengue, and how cities measure their biodiversity.
Module 4 turns to heat, floods and air: why cities run hotter and how to cool them, why flash floods hit so fast, what the Air Pollutant Index and the 2026 haze mean, the difference between mitigation and adaptation, and how to assess a neighbourhood's climate risk.
Module 5 follows the resources a city runs on: water lost through leaks and how to reuse it, waste and the recycling rules, energy in buildings and rooftop solar, and what urban farming can and cannot supply.
Module 6 is about land, housing and density: why cities spread faster than they grow, the 2026 housing crisis and Malaysia's affordability gap, upgrading informal settlements rather than clearing them, building around rail stations and the 15-minute city, and greening a neighbourhood without pricing its residents out.
Module 7 covers the governance, finance and community action that turn plans into change: environmental justice, how Malaysia's development plans work and when to object, paying for nature, free data tools and citizen science, how residents get heard, and a 90-day plan for your own neighbourhood.
A note on figures. Figures come from the latest official sources available in 2026, including the UN-Habitat SDG 11 Global Report 2026, the UN's World Urbanization Prospects 2025 and the Department of Statistics Malaysia. Where global and Malaysian figures use different definitions, the course says so.
Figures last checked: 20 October 2026.
- Plain language throughout, with Malaysian cases alongside international ones
- Built on 2026 sources, including the SDG 11 Global Report 2026
- Each quiz draws 10 questions randomly from a 30-question bank, so every attempt is different
- 7 modules, ending with a 90-day plan for your own neighbourhood
Course Content
Module 1: The City as an Ecosystem
Seeing cities as living systems
Why cities count as ecosystems, how resources flow through them, how fast the world and Malaysia are urbanising, and where SDG 11 stands in 2026.
Learning Objectives - Define urban ecology and describe where the field came from
- Distinguish ecology in, of and for the city
- Explain urban metabolism and the difference between linear and circular flows
- Describe how fast the world and Malaysia are urbanising, and why definitions matter
- Summarise the SDG 11 targets and the 2026 assessment of progress
What You'll Learn - What urban ecology studies, and its Chicago and Berlin roots
- Ecology in, of and for the city
- Urban metabolism, from Abel Wolman in 1965 to The Weight of Cities
- Linear and circular resource flows
- World Urbanization Prospects 2025 and the Degree of Urbanisation
- Malaysia's urbanisation curve from 1970 to 2020
- The ten SDG 11 targets and the New Urban Agenda
- The SDG 11 Global Report 2026
What Urban Ecology Is
Walk through any Malaysian city and you are walking through an ecosystem. Rain falls on roofs and roads, runs into monsoon drains and ends up in the Klang or the Gombak. Mynas and crows feed on what people throw away. Rain trees shade one street while the next bakes in the sun. Mosquitoes breed in a blocked gutter. None of this is separate from the people who live there.
Urban ecology is the study of how living things, people included, interact with each other and with the built and natural environment of towns and cities.
An idea with two roots
The word ecology was first borrowed for cities by sociologists. In the 1920s, Robert Park and Ernest Burgess at the University of Chicago described the city as a kind of ecological community in which groups of people competed for space, and The City (1925), written with Roderick McKenzie, set out the famous concentric zone model of how a city grows outwards in rings. That early
human ecology was about people, not plants or animals.
Biologists came to cities later. From the late 1950s, the botanist Herbert Sukopp and his colleagues in Berlin mapped the plants growing on rubble, railway land and wasteland, and showed that cities had their own distinct wild flora. In 1997 the United States added Baltimore and Phoenix to its
Long Term Ecological Research Network as its first urban sites, treating whole metropolitan areas as ecosystems to be studied over decades.
Why it matters now
Today urban ecology brings those strands together. It asks how cities affect nature, how nature affects city life, and how people's decisions change both. The questions are practical. Where should trees go to cool a street the most? Why do some neighbourhoods flood and others do not? Who has a park within walking distance, and who does not?
Those questions are urgent because so many people now live in cities, and because cities drive most emissions. The
Intergovernmental Panel on Climate Change estimates that urban areas accounted for 67 to 72% of global greenhouse gas emissions in 2020, counting the emissions caused by what city dwellers consume. What happens in cities decides much of what happens to the planet.
Watch video: What Urban Ecology Is
Key Insight: Urban ecology studies cities as ecosystems in which people are one of the species. It grew from Chicago sociologists in the 1920s and Berlin botanists from the late 1950s, and today it answers practical questions about trees, floods and parks.
Real-World Example: A blocked roadside drain in Shah Alam is an ecology problem as much as an engineering one. It holds standing water where mosquitoes breed, it backs up in a heavy storm, and it collects litter that washes into the river. Fixing it touches public health, flooding and pollution at the same time.
Q: Who first described the city as a kind of ecosystem, in the early twentieth century?
Robert Park and Ernest Burgess at the University of Chicago described the city as an ecosystem of competing human groups, and published The City in 1925. Biologists such as Herbert Sukopp in Berlin studied urban nature later, from the late 1950s.
Pick one street you use every day. What living things share it with you, and how do the choices people make on that street affect them?
Ecology In, Of and For the City
There are three ways to look at nature in a city, and the one you choose decides which questions you ask and what you can do with the answers.
Ecology in the city
The first approach studies nature that happens to sit inside a city: the birds in a park, the fish in an urban lake, the trees on a forested hill. The city is just the setting, and the ecologist treats a park much as they would treat a patch of forest. This tells you a lot about the patch and very little about the city around it. Survey the birds of Taman Tasik Perdana and you learn about Taman Tasik Perdana.
Ecology of the city
The second approach treats the whole city as one ecosystem. Roads, buildings, drains, people and money are all part of it, alongside soil, water and wildlife. In 2000 a group of American ecologists led by Nancy Grimm drew this distinction and argued that people must be inside the picture rather than treated as a disturbance from outside. It is the view behind the Baltimore and Phoenix research sites. It explains, for example, why the wealthiest neighbourhoods of a city often have the most trees: income, planning history and land prices shape where nature survives.
Ecology for the city
The third approach goes a step further. It uses ecological knowledge to help design and manage better cities, working with planners, engineers, designers and residents rather than only describing what is there. Writers such as Dan Childers in 2015 and Steward Pickett in 2016 described the field's path as a journey from ecology in, to ecology of, to ecology for the city. The aim is not only to understand but to improve: cooler streets, cleaner rivers, safer flood plains and fairer access to green space.
This course uses all three, but leans on the third. Each module asks what the evidence says, and then what a council, a developer or a residents' association can do with it.
Ecology In, Of and For the City - Three Approaches to Urban Nature
Key Insight: Ecology in the city studies a patch. Ecology of the city studies the whole system with people inside it. Ecology for the city uses that knowledge to design and manage better places.
Q: A team counts bird species in one city park and compares the result with a forest reserve. Which approach is this?
Studying nature inside one patch of a city, and treating the city only as the setting, is ecology in the city. Ecology of the city would ask how the whole urban system, people and money included, shapes the birds in that park.
Do you agree that people should be treated as part of the urban ecosystem rather than as a disturbance to it? What would change in how your town is planned if they were?
Urban Metabolism
A city cannot feed itself, power itself or clean up after itself from inside its own boundaries. Every day lorries bring in food, pipes bring in water, cables and pipelines bring in energy, and every day the city sends out sewage, rubbish, heat and exhaust.
Urban metabolism is the idea of tracking those flows, much as a doctor tracks what a body takes in and gives out.
Where the idea came from
The American engineer Abel Wolman introduced it in an article called "The Metabolism of Cities" in Scientific American in September 1965. Worried about worsening air and water pollution in American cities, he worked out the inflows and outflows of an imaginary American city of one million people: water, food and fuel coming in, and sewage, solid waste and air pollutants going out. His point was that pollution could not be fixed one pipe at a time. It was the result of how much flowed through the whole system.
Linear and circular
Most cities today run a
linear metabolism. Resources come in, are used once and leave as waste. Water is piped in from a dam, used once and flushed away; food is trucked in and the leftovers go to landfill. A
circular metabolism loops flows back into use. Treated wastewater is reused by industry, food waste becomes compost or biogas, and demolition rubble becomes new building material. Module 5 returns to these loops in detail.
Why the numbers matter
The scale is enormous. In The Weight of Cities, a 2018 report presented at the World Urban Forum in Kuala Lumpur, the
International Resource Panel of the UN Environment Programme estimated that the world's cities used about 40 billion tonnes of materials in 2010. Under business as usual, it projected about 90 billion tonnes by 2050, far more than the planet can sustainably supply. It also estimated that more efficient transport, commercial buildings and heating and cooling could cut resource use in those three sectors by about 46 to 67%.
Thinking in flows changes the question a council asks. Instead of "where do we put another landfill?", it becomes "why is so much coming in, and how much of it could stay in use?"
Urban Metabolism - Inputs, Outputs and the Circular Loop
Watch video: Urban Metabolism
Key Insight: Urban metabolism tracks what flows into a city and what flows out. Most cities run a linear metabolism that uses resources once and discards them. A circular metabolism loops them back into use.
Real-World Example: Think of one condominium block. Water arrives from the mains, electricity from the grid and groceries from the supermarket. Out go sewage, bins of rubbish and hot air from hundreds of air-conditioner units. Adding rainwater tanks, a composting corner and rooftop solar panels does not change what residents need, but it shortens and loops some of those flows.
Q: Which of these is an example of a circular urban metabolism?
A circular metabolism loops outputs back into use, as when treated wastewater is reused by industry. Using water or food once and discarding the remainder, or simply opening a new landfill, is a linear metabolism.
Action step: for one week, notice what flows into and out of your home or workplace: water, electricity, food, packaging and rubbish. Which single flow would be easiest to shorten or loop back into use?
The Urbanisation Curve
In 1950 only one person in five lived in a city. Today it is close to one in two, and the shift is far from over.
The global picture
The
World Urbanization Prospects 2025, published by UN DESA in November 2025, found that cities are home to
45% of the world's 8.2 billion people, up from 20% in 1950. Towns hold another 36% and rural areas 19%. Two-thirds of the world's population growth between now and 2050 is expected in cities, and most of the rest in towns. The number of megacities, urban areas of 10 million people or more, rose from 8 in 1975 to 33 in 2025, and 19 of them are in Asia. Jakarta, with nearly 42 million people, is now the largest. The same report projects that
Kuala Lumpur will pass 10 million people by 2050.
Watch the definition
The 2025 edition was the first to use one common yardstick for every country, the
Degree of Urbanisation. A city is a dense cluster of at least 50,000 people, and a town is a cluster of at least 5,000 people living at 300 or more per square kilometre. Countries still publish their own figures on their own definitions, so national and UN numbers can look very different. Malaysia's figure below uses the national definition and should not be compared directly with the UN's 45% for cities.
The Malaysian curve
According to the
Department of Statistics Malaysia,
75.1% of Malaysians lived in urban areas in 2020, up from 28.4% in 1970 and 50.7% in 1991. The urban population grew from 3.0 million to 24.4 million over those fifty years, while the rural population edged up only from 7.5 million to 8.1 million. Kuala Lumpur and Putrajaya are fully urban and Selangor is 95.8% urban, while Kelantan, at 44.1%, is the least urbanised state.
What changes on the ground
Urban growth turns farmland, forest and wetland into roads and roofs. Soil is sealed over, so rain runs off instead of soaking in. Habitat is cut into fragments. Local temperatures rise. And when cities spread outwards rather than upwards, people drive further and the bill for roads and pipes grows. Later modules take each of these in turn.
Malaysia's Urbanisation Curve - Census Figures, 1970 to 2020
Watch video: The Urbanisation Curve
Key Insight: The share of the world's people living in cities rose from 20% in 1950 to 45% in 2025. On its own national definition, Malaysia was 75.1% urban in 2020, and Kuala Lumpur is projected to become a megacity of 10 million by 2050.
Q: According to the Department of Statistics Malaysia, what share of Malaysians lived in urban areas in 2020?
Malaysia's urbanisation rate was 75.1% in 2020, up from 28.4% in 1970. The 50.7% figure is for 1991, 95.8% is Selangor alone, and the UN's 45% for cities uses a different definition.
Think about the area where you grew up. How has it changed over the last twenty years, and what was gained and lost as it became more built up?
SDG 11 in 2026
In 2015 every member state of the United Nations adopted 17 Sustainable Development Goals for 2030. Goal 11 is the urban one: make cities and human settlements inclusive, safe, resilient and sustainable.
Ten targets
SDG 11 has ten targets. Seven set outcomes: adequate and affordable housing and upgraded slums (11.1), safe and affordable transport (11.2), inclusive and participatory planning (11.3), protection of cultural and natural heritage (11.4), fewer deaths and losses from disasters (11.5), a smaller environmental impact per person, with attention to air quality and waste (11.6), and universal access to safe, green and public spaces (11.7). Three more cover the means: links between urban and rural areas (11.a), integrated policies and disaster risk reduction strategies (11.b), and support for the least developed countries to build sustainably (11.c).
The New Urban Agenda
A year later, at the Habitat III conference in Quito in October 2016, countries adopted the
New Urban Agenda, a 20-year guide to how cities should be planned, built and governed. In July 2026, at its midpoint, the UN General Assembly held a high-level meeting in New York and adopted a political declaration renewing that commitment to 2036.
The 2026 verdict
The SDG 11 Global Report 2026, launched by
UN-Habitat on 9 July 2026, is blunt: the world is off track. More than
3 billion people lack adequate housing, including over 1.1 billion in informal settlements and slums. Half of all households worldwide spend more than 30% of their income on rent. Disasters affected an average of 123 million people a year between 2015 and 2024. There is progress too. Across 126 countries, the share of urban residents with convenient access to public transport rose from 53.2% in 2020 to 61.5% in 2025, though four in ten still lack it, and in 123 countries land consumption is now more closely matched to population growth.
Where this leaves Malaysia
For a country that is three-quarters urban, SDG 11 is not an abstract goal. Housing costs, flash floods, heat, traffic and access to parks are all SDG 11 issues, and each has a module in this course. The question running through all of them is the one this module began with: what does it take for a city to work as a healthy ecosystem for the people and other species that live in it?
Key Insight: SDG 11 has ten targets covering housing, transport, planning, heritage, disasters, environmental impact and green space. The SDG 11 Global Report 2026 finds the world off track, with more than 3 billion people lacking adequate housing.
Q: According to the SDG 11 Global Report 2026, how many people lack adequate housing?
The report found that more than 3 billion people lack adequate housing. The 1.1 billion figure is the number living in informal settlements and slums, who are part of that larger total.
Which SDG 11 target feels most urgent where you live, and what would you point to as evidence?
Module 2: Green and Blue Infrastructure
The living systems a city runs on
Trees, parks, rivers, wetlands and green roofs: what they do for a city, how to plant and restore them well, and who gets to enjoy them.
Learning Objectives - Distinguish green, blue and grey infrastructure and explain how they work together
- Identify the four kinds of ecosystem service and the disservices urban nature can bring
- Explain how canopy cover, root space and species diversity decide how well street trees perform
- Compare river restoration and sponge city approaches with concrete channels
- Evaluate access to green space using the 3-30-300 rule and Malaysian planning standards
What You'll Learn - Grey, green and blue infrastructure, and nature-based solutions
- Seoul's Cheonggyecheon and the removal of an elevated highway
- Provisioning, regulating, cultural and supporting services
- Canopy cover, the right tree in the right place, and Kuala Lumpur's tree inspections
- Bishan-Ang Mo Kio Park, China's sponge cities and Kuala Lumpur's River of Life
- Green roofs, living walls and Singapore's skyrise greenery
- The 3-30-300 rule and the Kuala Lumpur Local Plan 2040
- Taman Rimba Kiara, Taman Danau Desa and why zoning is not protection
Green, Blue and Grey
Every city depends on infrastructure, the physical systems that keep it running. Most people picture the grey kind: pipes, monsoon drains, concrete canals, roads, retaining walls and sewage plants. Engineers can design
grey infrastructure to a precise standard, so a drain is sized for a certain storm and a wall is built to hold a certain slope. Its weakness is that it usually does one job, and it begins wearing out the day it is finished.
Green and blue
Green infrastructure is the network of living, planted spaces in a city: street trees, parks, forest reserves, playing fields, green roofs, private gardens and the soil beneath them.
Blue infrastructure is the water network: rivers, streams, lakes, ponds, wetlands and coasts. The
European Commission describes green infrastructure as a strategically planned network of natural and semi-natural areas, designed and managed to deliver a wide range of ecosystem services.
Unlike a drain, a park can do many jobs at once. It soaks up rain, shades the ground, shelters birds and insects, and gives people somewhere to walk and play. A tree also becomes more useful as it grows, at least for its first few decades, while a pipe only gets older.
Partners, not rivals
The choice is rarely green or grey. A city still needs pipes and sewage plants. The skill lies in combining them, so that green and blue spaces take some of the load off grey systems. Using nature deliberately to solve a problem in this way is called a
nature-based solution, a subject the Kyoik course
Nature-Based Solutions covers in depth.
When a city chose blue over grey
The best-known example is Seoul. In the decades after the Korean War, the Cheonggyecheon stream in the city centre was covered with concrete and later topped by an elevated highway. In 2003 the city began tearing the highway down, and in 2005 a restored stream about 5.8 kilometres long reopened as a linear park. Studies reported that the corridor runs several degrees cooler than nearby streets in summer, and that the number of plant, fish, bird and insect species along it rose sharply. It is not a wild river, since much of its water is pumped in, but it showed that a city can remove grey infrastructure and gain from doing so.
Grey, Green and Blue Infrastructure - What Each Does Best
Watch video: Green, Blue and Grey
Key Insight: Grey infrastructure is engineered and usually does one job. Green and blue infrastructure are living networks of planted spaces and water that do many jobs at once. Cities work best when the three are combined.
Real-World Example: A housing estate in Seremban drains into a concrete monsoon drain sized for a particular storm. Adding a planted swale along the road and a small retention pond beside the playground does not replace the drain, but it holds back the first rush of water, so the drain overflows less often.
Q: What is the main advantage of green infrastructure over grey infrastructure?
A park or row of trees can soak up rain, cool the ground, shelter wildlife and give people somewhere to relax, all at once. Grey infrastructure is built to a precise standard but usually does one job.
Think of one grey structure near your home, such as a drain, canal or bare car park. What could green or blue infrastructure add there, and what would it need to work?
Ecosystem Services in Cities
The benefits people get from nature are called
ecosystem services. The idea was popularised by the
Millennium Ecosystem Assessment, a United Nations-backed review of the world's ecosystems published in 2005, which sorted them into four groups.
Four kinds of service
Provisioning services are the things nature produces. In cities they include food from community gardens and fruit trees, and the clean water that flows from forested catchments.
Regulating services are the natural processes that keep a city liveable: shade and evaporation that cool the air, soil and plants that slow and soak up rain, leaves that trap some dust, and insects that pollinate.
Cultural services are the benefits to mind and community: exercise, calm, beauty and a sense of place, like a Sunday morning walk round Taman Tasik Titiwangsa.
Supporting services, such as soil formation, nutrient cycles and habitat, are the base the other three rest on.
The evidence on heat
Some of these services can be measured. A 2023 study in The Lancet looked at 93 European cities in the summer of 2015. It estimated that more than 4% of summer deaths in those cities were linked to the urban heat island effect, and that about a third of those deaths could have been prevented if tree cover had reached 30%. Heat is a growing risk in Malaysian cities too, and Module 4 returns to it.
Services and disservices
Nature in cities also brings costs, which ecologists call
ecosystem disservices. Old trees can drop branches or fall in storms. Roots can lift pavements and crack drains. Standing water can breed mosquitoes, and some plants trigger allergies. None of these is a reason to avoid urban nature, but they are reasons to design and maintain it well. A badly placed tree or a neglected pond can quickly turn residents against greening.
Why naming services matters
Naming services makes them visible when decisions are made. When a council weighs a car park against a park, the car park's income is easy to count in ringgit. The park's cooling, flood storage and health benefits are real but spread across many people, so they are easily missed unless someone puts them on the table.
Ecosystem Services - The Millennium Ecosystem Assessment Framework, 2005
Key Insight: Ecosystem services fall into four groups: provisioning, regulating, cultural and supporting. Urban nature also has disservices, such as falling branches and mosquito breeding, which good design and maintenance keep in check.
Q: Shade from street trees lowering the temperature of a pavement is which kind of ecosystem service?
Cooling through shade and evaporation is a regulating service, one of the natural processes that keep a city liveable. Provisioning services are things nature produces, such as food and water.
Which ecosystem services does the green space nearest to you provide? Which one would you miss most if it were built over?
Urban Forests and Street Trees
The trees of a city, on streets, in parks, in forest reserves and in private gardens, together make up its
urban forest. Foresters measure it mainly by
canopy cover, the share of land shaded by tree crowns when seen from above. Canopy is what delivers most of the benefits: shade on pavements and walls, evaporation that cools the air, and leaves and roots that slow down rainwater.
Losing cover quietly
Urban forests rarely disappear in one go. They thin out plot by plot, as gardens are paved over, old trees are removed and new developments plant fewer and smaller trees. One satellite study of Malaysian cities estimated that between 2000 and 2012, tree cover equal to about 3.5% of Kuala Lumpur's land area was lost, along with 6.9% in Penang, 9.5% in Johor Bahru and 17.4% in Pasir Gudang.
The right tree in the right place
A tree needs room for its roots as well as its crown. Planted in a narrow strip between a road and a building, it may grow tall but stay weakly anchored. In May 2024 a tree more than 50 years old fell on Jalan Sultan Ismail in Kuala Lumpur, killing one man, injuring two others and damaging 17 vehicles. An arborist suggested that restricted root space caused by surrounding development may have played a part.
Kuala Lumpur City Hall (DBKL) said it had been inspecting older city-centre trees since 2019, and had felled 147 of the 175 it had found to be high risk. After another fatal tree fall on Jalan Tun Razak in July 2026, DBKL began a fresh round of inspections of mature trees along the city's major roads.
The lesson is not to plant fewer trees but to plant and care for them properly: enough soil volume for the roots, species suited to the spot, and regular inspection by trained arborists as trees age.
Do not put all the eggs in one basket
Diversity matters too. A widely used guideline from the American tree geneticist Frank Santamour suggests that no single species should make up more than 10% of a city's trees, no genus more than 20% and no family more than 30%. A street lined with a single species can lose all its shade to one pest or disease. Native species also tend to support more local insects and birds, a theme Module 3 picks up.
Key Insight: Canopy cover, the share of land shaded by tree crowns, delivers most of a city's tree benefits. Trees need root space, suitable species, regular inspection and enough diversity to survive pests and storms.
Q: What does Frank Santamour's guideline say about a city's trees?
Santamour's guideline limits any one species to 10% of a city's trees, any genus to 20% and any family to 30%, so that a single pest or disease cannot strip a whole city of its shade.
Look at the trees on your street. Do they have room to grow, roots included? Are most of them the same species?
Rivers, Wetlands and Sponge Cities
For much of the twentieth century, cities treated rivers as drains. Streams were straightened, lined with concrete and sometimes covered over, so that water would leave the city as fast as possible. That approach pushes floods further downstream, strips out habitat and turns rivers into places people avoid.
From canal to river in Singapore
Singapore's Bishan-Ang Mo Kio Park shows the opposite approach in a tropical city. A 2.7 kilometre concrete canal on the Kallang River was replaced with a meandering river about 3 kilometres long, its banks held by plants and natural materials rather than concrete. Opened in March 2012 by the national water agency PUB and the National Parks Board under the
Active, Beautiful, Clean Waters programme, it uses the surrounding park as a floodplain. In heavy rain the lawns double as part of the channel, raising its carrying capacity by about 40%. Otters have since returned to the river.
Sponge cities
China has taken the idea to national scale. In 2015 it launched a
sponge city programme, associated with the landscape architect Kongjian Yu, to make cities absorb, store and reuse rainwater instead of shedding it. Thirty pilot cities were chosen in two batches in 2015 and 2016. Guidelines from the State Council set a target that by 2030 about 80% of urban areas should absorb and reuse at least 70% of their rainwater, using permeable paving, rain gardens, wetlands and green roofs. Progress has been uneven, and record storms have shown that sponge features alone cannot handle every extreme event.
The River of Life in Kuala Lumpur
Kuala Lumpur's River of Life project set out to clean the Klang and Gombak rivers and turn the riverfront around Masjid Jamek into a public space. Its goal was to raise water quality from Class III and IV, unsuitable for body contact, to Class IIB, suitable for recreation, by 2020. The riverfront has been transformed, with walkways and the Blue Pool water feature where the two rivers meet. But in 2024 the Auditor-General reported that the water quality goal had not been met, and that only 50 of the 296 sewage treatment plants involved had been rationalised or upgraded. A beautiful riverfront cannot be cleaner than what flows into the river upstream.
Watch video: Rivers, Wetlands and Sponge Cities
Key Insight: Restoring rivers works with water rather than against it. Bishan-Ang Mo Kio Park and China's sponge cities store and slow rain, while Kuala Lumpur's River of Life shows that a riverfront cannot be cleaner than what flows in upstream.
Q: According to the Auditor-General in 2024, why had the River of Life not met its water quality goal?
Only 50 of the 296 sewage treatment plants involved had been rationalised or upgraded. The riverfront itself had been transformed, but pollution entering the rivers upstream kept water quality below the Class IIB target.
Is there a concrete river or canal near you? What would it take to turn it into a place people want to spend time beside?
Roofs, Walls and Small Spaces
In a dense city, ground space is expensive and mostly taken. So greening moves up, onto roofs and walls, and into the small leftover spaces between buildings.
Green roofs
A
green roof is a layer of growing medium and plants laid over waterproofing.
Extensive roofs have a thin layer, usually no more than about 15 centimetres, planted with hardy grasses and succulents, and need little care.
Intensive roofs have deeper soil that can carry shrubs and even trees, like a park on a building, and need a stronger structure, irrigation and regular gardening.
Green roofs cool the building beneath them. On a tropical test bed in Singapore, researchers found that a green roof surface ran about 7°C cooler than a bare roof during the day, though the air above it was only about half a degree cooler. Green roofs also hold back rain. Studies in cooler climates have found that extensive roofs retain anywhere from about a quarter to four-fifths of annual rainfall, depending on soil depth and storm size. The evidence for heavy tropical downpours is thinner, and a roof that is already soaked holds little more.
Green walls
Vertical greenery ranges from climbing plants on a simple trellis to modular living walls with built-in irrigation. Climbers are cheap and robust. Living walls look striking but need water, nutrients and regular maintenance, and some fail within a few years once that care stops.
Singapore's skyrise greenery
Singapore has made greening buildings a matter of policy. Its target is 200 hectares of skyrise greenery by 2030, and by May 2023 it had reached about 155 hectares. The Urban Redevelopment Authority's LUSH programme asks developers to replace greenery lost at ground level with greenery on the building and rewards them for it, while a separate incentive scheme has paid up to half the cost of greening existing buildings.
Small spaces add up
Pocket parks, planted road verges, school fields and the strips along drains are easy to overlook. Yet for many residents they are the nearest green space there is, and the next section shows why distance to green space matters so much.
Key Insight: Green roofs and walls bring greenery into dense cities. Roofs cool the building beneath and hold back some rain, while living walls need ongoing water and care. Singapore aims for 200 hectares of skyrise greenery by 2030.
Real-World Example: A Petaling Jaya office block has a flat concrete roof that bakes in the afternoon sun. An extensive green roof would add little weight and need little upkeep, cooling the top floor and holding back some rain. A roof garden with trees would need an engineer to check the structure first.
Q: In the Singapore test bed, what did the green roof cool the most?
The green roof surface ran about 7°C cooler than a bare roof during the day, while the air above it was only about half a degree cooler. Green roofs mainly cool the building beneath them.
Action step: look at the roofs you can see from your home or office. Which one could carry greenery, and who would need to agree to it?
Who Gets the Green?
Green space only helps people who can reach it. A large park on the edge of town does little for a family in a flat across the city with no car. So planners now look not only at how much green space a city has, but at who lives near it.
The 3-30-300 rule
In 2021 the urban forester Cecil Konijnendijk proposed a simple rule of thumb, the
3-30-300 rule, now used by hundreds of municipalities. Every home, school and workplace should have at least
3 trees in view. Every neighbourhood should have at least
30% tree canopy. And nobody should live more than
300 metres from the nearest public green space. Many cities pass the first test easily and struggle with the other two, especially in dense centres.
Malaysia's standards
Malaysia's national planning standard, approved by the National Physical Planning Council in 2005, set a target of 2 hectares of open space for every 1,000 people. Kuala Lumpur's Local Plan 2040, gazetted in May 2025 and in force since June 2025, aims for at least 20 square metres of open space per resident by 2040, the same ratio. For a projected 2.35 million people that comes to about 4,700 hectares, against roughly 2,500 hectares zoned today. It protects public open space through zones OS1 and OS2, private open space through OS3, and a newer OS4 layer for public open space inside private developments.
Zoning is not protection
Zoning shows what land is meant for, but on its own it does not guarantee that a park stays a park. Stronger protection comes from formally gazetting the land as open space under the National Land Code. Two Kuala Lumpur cases show the stakes. In Taman Tun Dr Ismail, residents fought plans for luxury apartment blocks of up to 52 storeys on part of Taman Rimba Kiara. In April 2023 the Federal Court upheld a ruling that the development order was void, because it contravened the city's planning law and its structure plan. In Taman Danau Desa, a neighbourhood playground zoned as public open space in earlier plans was earmarked for high-rise housing in the 2040 plan, and residents lodged more than a thousand objections. When the mayor opened a window for amendments to the plan in June 2026, community groups pushed to restore green spaces that had been dropped.
As Module 1 noted, wealthier areas often have the most trees. Measuring access street by street shows where greening should go first.
The 3-30-300 Rule - Trees in View, Canopy Cover and Distance to Green Space
Watch video: Who Gets the Green?
Key Insight: Access matters as much as area. The 3-30-300 rule asks for three trees in view, 30% canopy and green space within 300 metres. Kuala Lumpur's 2040 plan aims for at least 20 square metres of open space per resident by 2040, but zoning alone does not protect a park.
Real-World Example: A councillor wants to know which neighbourhood needs a pocket park first. Mapping every home's walking distance to public green space reveals a cluster of flats more than 300 metres from any park, even though the district as a whole meets the 2 hectares per 1,000 people standard. Averages can hide the gaps.
Q: Under the 3-30-300 rule, what is the furthest anyone should live from public green space?
The rule says nobody should live more than 300 metres from the nearest public green space. The 3 refers to trees in view from home, school and work, and the 30 to the percentage of tree canopy in a neighbourhood.
How far is your home from the nearest public green space you would actually use? Would your neighbourhood pass the 3-30-300 test?
Module 3: Urban Biodiversity and Health
Who shares the city with us, and why it matters
Which species thrive in cities and which disappear, how corridors and native planting keep nature connected, how to handle invasive species and wildlife conflict, and how drains and design shape dengue.
Learning Objectives - Classify urban species as avoiders, adapters or exploiters, with Malaysian examples
- Explain how fragmentation affects wildlife and how corridors and stepping stones help
- Explain why native and layered planting support more wildlife
- Identify invasive species and the causes of human-wildlife conflict in Malaysian towns
- Explain how urban design and maintenance affect dengue, and how Wolbachia works
- Describe how cities measure biodiversity and what Target 12 of the global framework asks for
What You'll Learn - Urban avoiders, adapters and exploiters, and biotic homogenisation
- House crows in Penang and Klang
- Patches, corridors, stepping stones and the Central Forest Spine
- Eco-Link@BKE and Penang's canopy bridges for dusky langurs
- Native plants, fig trees, layered planting and street-scale rewilding
- Invasive species, macaques and Perhilitan's complaint figures
- Aedes breeding, dengue in 2024 to 2026, the 1975 Act and Wolbachia
- The Singapore Index, Target 12 and COP17 in Yerevan
Who Lives in Cities
Cities are not empty of wildlife. They hold their own communities of plants and animals, but not the same ones that lived there before. Ecologists sort species by how they respond to urban growth into three broad groups.
Avoiders, adapters and exploiters
Urban avoiders disappear as a city grows. They need large areas of undisturbed habitat or are sensitive to people, noise and light. In Malaysia they include most forest-interior birds and large mammals such as the Malayan tapir, which turns up in towns only when it strays from shrinking forest.
Urban adapters mainly use natural food and shelter but can also take advantage of what people provide. Long-tailed macaques, Asian water monitors, common palm civets and garden birds such as sunbirds fall here.
Urban exploiters depend heavily on people for food and shelter. Rats, feral pigeons and the house crow are typical examples.
The groups are a simplification of a gradual range, but they explain a common pattern. As cities grow, avoiders are lost and exploiters multiply, so cities around the world come to share the same few species. Ecologists call this
biotic homogenisation.
The house crow
The house crow is native to South Asia and has spread to more than 20 countries, travelling with people and thriving on their waste. In Malaysia it is an invasive species in coastal towns, noisy, messy around food courts and aggressive towards native birds. The Penang Island City Council culled 17,750 crows in 2025, down from 23,336 in 2024, and the Klang Royal City Council had culled nearly 6,000 by mid-September 2026. Researchers at Universiti Malaya link crow numbers to poorly managed food waste, and the Penang council itself warns that crows can return quickly if food waste and bins are not managed. As long as bins overflow, the crows come back.
Nature in the middle of the city
Cities can still hold rich biodiversity where habitat survives. The Bukit Nanas forest reserve, now the KL Forest Eco Park, keeps a patch of lowland rainforest in the heart of Kuala Lumpur, at the foot of the KL Tower. The question for planners is how to keep such places, and how to connect them.
Watch video: Who Lives in Cities
Key Insight: Cities favour urban exploiters, such as rats, pigeons and house crows, and lose urban avoiders, such as forest-interior birds. Left unchecked, this makes cities everywhere share the same few species. Managing food waste matters more than culling.
Q: Which category does the house crow fall into in Malaysian cities?
The house crow is an urban exploiter: it depends heavily on people, especially their food waste. It is also an invasive species in Malaysia, originally from South Asia.
Which animals do you see most often around your home or office? Would you call them avoiders, adapters or exploiters, and what does that tell you about the area?
Fragmentation and Corridors
When a forest is cleared for a road, a housing estate or a plantation, what is left is often not one smaller forest but many separate pieces. This is
habitat fragmentation, and it is one of the main ways cities harm wildlife.
Why fragments lose species
Small patches hold fewer animals, so local populations are more likely to die out. Patches also have more edge for their size, and edges are hotter, drier, brighter and noisier than the forest interior. Animals that try to move between patches must cross roads, fences and gardens, and many are killed on the way. Over time, isolated fragments tend to lose species. The
Department of Wildlife and National Parks (Perhilitan) has said that broken forest corridors force wildlife through human settlements in search of food, which is one reason conflict in towns is rising.
Patches, corridors and stepping stones
Landscape ecologists describe a landscape as
patches of habitat set in a
matrix of other land uses.
Corridors are continuous strips of habitat, such as a forested river reserve, that link patches.
Stepping stones are small patches, such as a pocket park or a large garden, close enough together that birds, bats and insects can hop between them.
Reconnecting the landscape
At the national scale, Malaysia's Central Forest Spine master plan, approved by the government in July 2022, identified 39 ecological linkages to reconnect eight major forest complexes in Peninsular Malaysia. In cities, the scale is smaller but the idea is the same. Singapore's Eco-Link@BKE, completed in 2013 as the region's first wildlife crossing, carries a strip of forest over an expressway between the Bukit Timah and Central Catchment nature reserves, and pangolins, palm civets and lesser mousedeer have been recorded using it. Singapore also aims to have 500 kilometres of park connectors by 2030.
In Penang, the Langur Project Penang builds canopy bridges from repurposed fire hoses so that endangered dusky langurs can cross roads above the traffic. Its founder, Yap Jo Leen, recorded eight langurs killed by vehicles between 2016 and 2018. The project's third bridge, in Batu Ferringhi, was installed in April 2026 and recorded its first langur crossing on 1 June.
Landscape Connectivity - Patches, Corridors and Stepping Stones
Watch video: Fragmentation and Corridors
Key Insight: Fragmentation breaks habitat into small, isolated patches that lose species over time and push wildlife into towns. Corridors and stepping stones, from the Central Forest Spine to a canopy bridge over a road, reconnect them.
Q: What is a stepping stone in landscape ecology?
Stepping stones are small patches of habitat, such as pocket parks and large gardens, close enough together for birds, bats and insects to move between bigger patches.
Is there a forest, river reserve or large park near you that is cut off from other green areas? What small change could help wildlife move between them?
Native Planting and Rewilding
Not all green space is equal for wildlife. A lawn of imported grass with a few ornamental palms looks green from above, but it feeds very little.
Why native plants matter
Most plant-eating insects can feed only on plants they have evolved alongside. Native plants therefore support far more caterpillars, beetles and other insects than exotic ones, and those insects are the food that many birds need to raise their young. A 2018 study in the United States, by Desirée Narango and colleagues, followed Carolina chickadees nesting in more than 160 suburban yards around Washington, D.C. Where native plants made up less than about 70% of the plant biomass, the chickadees failed to raise enough young to sustain their numbers.
The same logic applies in the tropics. Native fig trees are a keystone resource in Malaysian towns, because their fruit feeds birds, bats and squirrels at times of year when little else is available. Native pioneer shrubs such as simpoh air flower and fruit freely and draw in bees and birds.
Layers, not lawns
Forests have layers: ground cover, shrubs, small trees and a high canopy.
Layered planting copies that structure, so that one strip of land offers food and shelter at several heights. Singapore's Nature Ways programme plants layered native greenery along roads to link parks and nature areas, so that birds and butterflies can travel through the city.
Rewilding at street scale
Rewilding usually brings to mind large reserves, but much can be done on a single street. Councils can mow verges less often, leave leaf litter and fallen wood in planted beds, plant flowering natives instead of turf, and stop spraying insecticide where it is not needed. These steps often cost less than intensive maintenance.
There are limits. Not every native tree suits a narrow roadside strip, some residents see untidy verges as neglect, and long grass near homes can hide snakes or collect rubbish. The answer is to explain what is being done and why, to keep paths and edges neat, and to choose the right plant for each place.
Key Insight: Native plants feed the insects that birds and other wildlife depend on, and layered planting offers food and shelter at several heights. Mowing less, leaving leaf litter and planting natives can rewild a street at low cost.
Real-World Example: A residents' association in Shah Alam replaces a strip of turf along a drain with native shrubs, a few fig trees and ground cover. The council agrees to mow only the edge beside the path. Within a year, sunbirds and butterflies are regular visitors, and the strip needs less maintenance than the lawn did.
Q: In the 2018 study of suburban yards near Washington, D.C., what happened where native plants made up less than about 70% of plant biomass?
Below about 70% native plant biomass, the chickadees could not find enough insects to raise enough young to sustain their numbers. Native plants support far more of the insects that birds feed to their chicks.
Action step: find out what is planted in the nearest public green space or your own garden. How much of it is native, and what one native plant could you add?
Invasives, Pests and Conflict
Some of the wildlife problems in Malaysian towns come from species that should not be here at all. Others come from native animals pushed into closer contact with people.
Invasive species
An
invasive alien species is one that people have moved outside its native range, which then spreads and causes harm. Cities are hubs for them, because they receive so many goods, plants and pets from elsewhere. Besides the house crow, examples in Malaysian towns include the Javan myna, an introduced bird that Singapore's National Parks Board links to the decline of native birds such as the common myna and the magpie-robin, and the red-eared slider, an American pet turtle often released into ponds and lakes, where it competes with native turtles. Once established, invasive species are very hard to remove, so prevention matters most: not releasing pets, checking imported plants and not dumping aquarium water into drains.
Conflict with native wildlife
Human-wildlife conflict is rising. Perhilitan recorded 80,710 wildlife complaints in Peninsular Malaysia between 2020 and 2025, rising from 11,818 in 2020 to a peak of 15,492 in 2024, before easing to 13,885 in 2025. Long-tailed macaques were the most common cause, with 48,539 complaints over the six years, ahead of wild boar and elephants. In Selangor alone, Perhilitan received 18,444 complaints between 2023 and May 2025, most of them about monkeys.
Treat the cause, not just the symptom
Macaques come into housing areas for two main reasons: their forest is shrinking or cut off, and people make food easy to find. Open bins, food left out and deliberate feeding teach troops that houses are a reliable source of meals, and fed macaques become bolder and more aggressive. Relocating or culling a troop removes the animals but not the reason they came, so another troop often moves in.
The longer-lasting answers are monkey-proof bins, regular rubbish collection, a ban on feeding enforced with education, and protecting the corridors that let wildlife move without passing through gardens. Many other city animals, such as water monitors in drains, are harmless scavengers that help clean up waste and are best left alone.
Key Insight: Invasive species are best stopped before they spread. Conflict with native wildlife such as macaques is driven by habitat loss and easy food, so securing bins and stopping feeding works better in the long run than removing animals.
Q: Which species accounted for the most wildlife complaints to Perhilitan between 2020 and 2025?
Long-tailed macaques were the most common cause, with 48,539 of the 80,710 complaints recorded over the six years, ahead of wild boar and elephants.
Have you seen macaques, crows or other animals raiding bins near you? What would it take for your neighbourhood to stop giving them easy food?
Mosquitoes, Drains and Dengue
Dengue is an urban ecology problem. The virus is carried by
Aedes mosquitoes, mainly Aedes aegypti and Aedes albopictus, which breed in small pools of clean standing water: flower pot trays, blocked roof gutters, discarded containers, water tanks without lids, tyres and the puddles of construction sites. The way a town is built and maintained decides how many breeding sites it offers.
The numbers
According to the
Ministry of Health and the Department of Statistics, Malaysia recorded 123,133 dengue cases in 2023 and 122,423 in 2024. Cases then fell sharply in 2025: between 1 January and 5 July there were 32,299 cases, 58.6% fewer than in the same period of 2024. In 2026 they rose again. By epidemiological week 35, Malaysia had recorded 65,979 cases, 66% more than the 39,616 at the same point in 2025, and 62 deaths against 32.
Designing out breeding sites
The most reliable way to control Aedes is to remove the water it breeds in. That means drains laid with enough slope to empty fully and cleared of litter, roof gutters that are cleaned, covered water tanks, and construction sites that are inspected and kept free of pooled water. Under the Destruction of Disease-Bearing Insects Act 1975, health officers can issue a compound of up to RM500 when larvae are found on premises. In court, a first offence carries a fine of up to RM10,000, up to two years in jail, or both, rising to RM50,000, five years, or both for a repeat offence. Courts have fined construction firms as much as RM40,000 for breeding Aedes on their sites.
Using biology: Wolbachia
A newer tool works with ecology rather than chemicals. Wolbachia is a bacterium that, when introduced into Aedes aegypti, makes it much harder for the dengue virus to grow inside the mosquito. Once released, Wolbachia mosquitoes spread the bacterium through the local population. A peer-reviewed study by Malaysia's Institute for Medical Research and the University of Melbourne, published in 2024, found that dengue fell by an average of 62% at 20 release sites in high-rise residential areas compared with 76 control sites. By August 2025, 60 localities had taken part in the programme.
Wolbachia supports, but does not replace, removing breeding sites. A clean drain is still the first line of defence.
Watch video: Mosquitoes, Drains and Dengue
Key Insight: Aedes mosquitoes breed in small pools of clean standing water, so drains, gutters, tanks and construction sites decide how much dengue a town has. Wolbachia releases cut dengue by an average of 62% at Malaysian study sites.
Real-World Example: A district health office maps dengue cases in a Klang Valley township and finds a cluster around a stalled construction site. Inspectors find larvae in pooled water in the foundations and issue a compound. The developer pumps out the site, and cases in the cluster fall over the following weeks.
Q: Where do Aedes mosquitoes typically breed?
Aedes mosquitoes breed in small pools of clean standing water, such as flower pot trays, blocked gutters, discarded containers and construction sites. Removing that water is the most reliable control.
Action step: walk around your home or workplace this week and look for standing water in pots, gutters, containers and drains. How many possible breeding sites did you find?
Measuring and Committing
A city cannot manage what it does not measure. Two tools help cities track urban biodiversity and link local action to global goals.
The Singapore Index
The
Singapore Index on Cities' Biodiversity was developed by Singapore's National Parks Board with the Secretariat of the Convention on Biological Diversity, through workshops held between 2009 and 2011. It was designed as a self-assessment tool that lets a city benchmark itself against its own past scores. A revised edition published in September 2021 uses
28 indicators: 9 on native biodiversity, 5 on ecosystem services, and 14 on governance and management. Each indicator is scored from 0 to 4, giving a maximum of 112 points. The index is meant to track one city's progress over time rather than to rank cities against each other, since every city starts from a different landscape.
Target 12 of the global framework
In December 2022, at COP15 in Montreal, countries adopted the Kunming-Montreal Global Biodiversity Framework, with 23 targets for 2030.
Target 12 is the urban one. It calls for a significant increase in the area, quality and connectivity of green and blue spaces in cities and densely populated areas, and in people's access to them and the benefits they bring, through biodiversity-inclusive urban planning. Its headline indicator is the average share of a city's built-up area that is green or blue space for public use. The target links directly to SDG target 11.7 on green and public spaces.
COP17 in Yerevan
The next big moment is COP17, held in Yerevan, Armenia, from 19 to 30 October 2026. It carries out the first global review of progress under the framework, and a UN report launched just before the conference, the State of Biodiversity Action report, found that efforts remain off track to meet the 2030 targets, with none of the 23 targets showing a fully positive picture. COP17 is also reviewing the plan of action for subnational governments and cities, and the 9th Summit for Subnational Governments and Cities is due to meet on 24 October as part of the conference.
From index to action
Measurement matters only if it changes decisions. A council that scores itself on the Singapore Index learns where it is weakest, whether in native species, connectivity or governance, and can set targets for the next local plan. Malaysia's National Policy on Biological Diversity 2022-2030 carries the global targets into national policy, but much of the work of Target 12 falls to local councils.
The Singapore Index - 28 Indicators in Three Groups, Revised 2021
Key Insight: The Singapore Index lets a city score its own biodiversity on 28 indicators and track progress over time. Target 12 of the global framework asks for more, better connected and more accessible green and blue spaces in cities.
Q: How many indicators does the revised Singapore Index on Cities' Biodiversity use?
The 2021 edition uses 28 indicators, 9 on native biodiversity, 5 on ecosystem services and 14 on governance and management. Each is scored 0 to 4, so 112 is the maximum score, not the number of indicators.
If your local council scored itself on the Singapore Index, which of the three groups, native biodiversity, ecosystem services or governance, do you think it would score worst on, and why?
Module 4: Heat, Floods and Air
How cities change their own climate, and how to adapt
The urban heat island and how to cool a city, flash floods and stormwater, air quality and haze, the difference between mitigation and adaptation, and how to assess a neighbourhood's climate risk.
Learning Objectives - Explain the causes of the urban heat island and how heat affects health in Malaysia
- Compare shade, surface and ventilation measures for cooling a city
- Explain why cities flood quickly and what drains, tunnels and green features can and cannot do
- Interpret the Air Pollutant Index and describe the sources of urban air pollution and haze
- Distinguish mitigation from adaptation and recognise maladaptation
- Assess a neighbourhood's climate risk using hazard, exposure and vulnerability
What You'll Learn - Why cities run hotter, and MetMalaysia's heat levels
- Heat-related illness in Malaysia in 2026
- Cool roofs, shade, ventilation and the trouble with air conditioning
- Kuala Lumpur's first Heat Action Plan pilot
- Runoff, drain capacity, the 6 May 2026 floods and the SMART Tunnel
- The 13th Malaysia Plan flood allocation
- PM2.5, the Air Pollutant Index and the 2026 haze
- Mitigation, adaptation, co-benefits and maladaptation
- A step-by-step neighbourhood climate risk assessment
The Urban Heat Island
Cities are usually warmer than the countryside around them, and the gap is often largest at night. This is the
urban heat island, and it is one of the clearest ways a city changes its own climate.
Why cities run hot
Four things drive it. Dark surfaces such as asphalt, concrete and roofing absorb sunlight during the day and release the stored heat after sunset, so the city cools slowly at night. There are fewer trees and less open soil, so less water evaporates to cool the air. Vehicles, factories and air-conditioning units add
waste heat. And tall buildings close together form street canyons that trap heat and block the wind.
Scientists measure two kinds of heat island. The
surface heat island is how hot roofs, roads and ground get, usually mapped from satellites. The
air heat island is the temperature people actually breathe, measured by weather stations. Surfaces can be far hotter than the air above them.
The heat island in the Klang Valley
A 2019 study of Greater Kuala Lumpur compared 2016 hourly records from urban stations in Petaling Jaya and Subang with a suburban station in Sepang. The largest monthly average heat island it found was about 1.7°C, at Petaling Jaya in June. That sounds small, but it is an average across a whole month. On a still evening in a dense street, the difference people feel can be much larger.
When heat becomes dangerous
The
Malaysian Meteorological Department (MetMalaysia) issues hot weather alerts in levels. Level 1 means daily highs of 35°C to 37°C for at least three days in a row, and Level 2, a heatwave, means 37°C to 40°C for at least three days. In late March 2026 several districts in Kedah, including Kota Setar, Pendang, Pokok Sena and Baling, reached heatwave status, and in April Kota Setar hit 40°C. By 7 July 2026 the Ministry of Health had recorded 73 heat-related illness cases for the year, including four deaths, two of them young children.
Heat does not fall on everyone equally. Outdoor workers, older people living alone, young children and families in crowded flats without air conditioning face the greatest risk, and a heat island makes their nights harder to recover in.
The Urban Heat Island - Temperature Across a City, Rural Edge to Centre
Key Insight: Dark surfaces, few trees, waste heat and street canyons make cities warmer than the countryside, especially at night. Heat is a growing health risk in Malaysia, with 73 heat-related illness cases and four deaths recorded by July 2026.
Q: Why do cities often stay warmer than the countryside at night?
Dark, dense materials such as concrete and asphalt absorb heat during the day and release it slowly after sunset, so cities cool down more slowly than the countryside.
Think about the hottest place you pass through on a normal day. What makes it so hot: surfaces, a lack of shade, traffic, or the way the buildings are arranged?
Cooling the City
A city has three main levers for keeping cool:
shade,
surfaces and
air movement. The most effective plans use all three.
Shade
Shade stops sunlight reaching people and surfaces in the first place. Trees are the best source, because they also cool the air by evaporating water through their leaves, as Module 2 showed. Covered walkways, awnings and shaded bus stops matter too, especially on the routes people walk every day.
Surfaces
Dark surfaces absorb most of the sunlight that hits them, while light ones reflect it. A surface's reflectivity is called its
albedo. Measurements by the Lawrence Berkeley National Laboratory in the United States found that on clear days at solar noon, conventional roofing ran about 40°C hotter than the air, while high-albedo coatings ran only about 5°C hotter. Cool roofs and cool pavements cut the heat a building takes in and the heat a street gives off at night. They work best on large flat roofs that get full sun.
Air movement
Wind carries heat away. Planners can keep
ventilation corridors open, such as river valleys, wide roads and gaps between tower blocks, so that breezes can flow through a district instead of being blocked by a solid wall of buildings. Singapore uses wind and heat modelling when planning new towns for this reason.
The trouble with air conditioning
Air conditioning keeps people safe indoors, but it moves heat from inside a building to the street outside and uses large amounts of electricity, adding emissions. A city that relies only on air conditioning gets hotter outdoors, which drives yet more air conditioning. Passive cooling through shade, surfaces and ventilation breaks that cycle.
Kuala Lumpur's first Heat Action Plan
Kuala Lumpur City Hall and the C40 Cities network are piloting the city's first Heat Action Plan. Through an urban climate resilience programme with the Z Zurich Foundation and Zurich Malaysia, they have worked in Kampung Pasir Baru and the PPR Beringin public housing estate, mapping heat and building outdoor shade structures and a cooling centre where residents can rest on hot days. These pilots are meant to feed into a city-wide plan.
Watch video: Cooling the City
Key Insight: Cities cool down through shade, reflective surfaces and air movement. Air conditioning protects people indoors but heats the street outside and adds emissions, so passive cooling has to come first.
Real-World Example: A school in Alor Setar has a dark metal roof, an unshaded car park and classrooms that bake by noon. Painting the roof with a reflective coating, planting trees along the car park edge and opening high windows on both sides of each classroom cools the rooms without adding a single air-conditioning unit.
Q: Why does a high-albedo roof stay cooler than a dark one?
Albedo is a surface's reflectivity. A high-albedo roof reflects much of the sunlight that hits it, so it absorbs less heat. In one set of measurements it ran about 5°C above the air at noon, against about 40°C for conventional roofing.
Of shade, surfaces and air movement, which would make the biggest difference to the street or building where you spend most of your day? Who would need to act?
Flash Floods and Stormwater
A
flash flood rises within hours of heavy rain. In Malaysian cities it is usually caused not by a river bursting its banks but by more rain than the drains can carry.
Why cities flood fast
On natural ground, much of the rain soaks in or evaporates and only a small share runs off. When the ground is sealed under roofs and roads, far more of it runs off, and it reaches the drains much faster. Drains are designed for storms of a certain intensity. When rain falls harder than that, or when inlets are blocked with litter and silt, the water has nowhere to go.
That is what happened on 6 May 2026, when a thunderstorm dropped 96.5 mm of rain in one hour at the Universiti Malaya station, far above the warning levels of the
Department of Irrigation and Drainage. Sungai Toba and another river rose above their danger levels, flooding Segambut Dalam, Pantai Dalam and roads near Bukit Jalil, and Jalan Kuchai Lama also went under water. DBKL says drainage upgrades have cut the city's flood hotspots from more than 30 to 14, and it sends a task force to clear drain inlets whenever rain exceeds 22 mm an hour.
The cost of big floods
The floods of December 2021 and early 2022 showed what is at stake. The Department of Statistics estimated losses of about RM6.1 billion, around 0.4% of GDP, with roughly half of it in Selangor. Dozens of people died.
The SMART Tunnel
Kuala Lumpur's best-known flood defence is the SMART Tunnel, a 9.7 kilometre tunnel that opened to traffic in May 2007. Its middle 3 kilometres double as a two-deck motorway. In a severe storm it switches to its fourth mode: the motorway is closed and the whole tunnel carries floodwater away from the city centre. In December 2021 it diverted about 5 million cubic metres. But it protects only the catchment it serves, and many of the city's flash floods happen in areas outside its reach.
The next five years
The
13th Malaysia Plan for 2026 to 2030 sets aside about RM20 billion for 103 flood mitigation plan projects, including the Langat and Buloh rivers in Selangor, along with better early warning using data and AI-based forecasting. Big grey projects are only part of the answer. The green and blue measures in Module 2, such as retention ponds, swales and permeable paving, handle the many local storms that big projects cannot reach.
Runoff and Paving - How Sealed Surfaces Send More Rain to the Drains
Watch video: Flash Floods and Stormwater
Key Insight: Sealed surfaces send more rain into the drains, and faster, so intense storms overwhelm them. Big projects such as the SMART Tunnel protect some catchments, but local green and blue measures are needed for the many small storms.
Q: Why do heavily paved areas flood faster than natural ground in the same storm?
On natural ground about half the rain soaks in and only a small share runs off. On heavily paved land more than half runs off, and it reaches the drains much faster, so they are overwhelmed sooner.
Has your street or route to work flooded in a heavy storm? Where did the water come from, and where would you put a retention pond, swale or clearer drain?
Air Quality and Haze
Clean air is one of the SDG 11 targets (11.6), and in Malaysia air pollution has two very different sources: what cities produce themselves, and smoke that drifts in from fires across the border.
Fine particles
The pollutant of most concern is
PM2.5, particles smaller than 2.5 micrometres across, small enough to reach deep into the lungs and the bloodstream. Local sources include vehicle exhaust, industry, construction dust and open burning. In 2021 the World Health Organization tightened its guideline for annual average PM2.5 to 5 micrograms per cubic metre. According to the 2025 World Air Quality Report, as summarised by Greenpeace Malaysia, Malaysia's national average fell from 18.3 to 16 micrograms per cubic metre between 2024 and 2025, and Kuala Lumpur's from 17.7 to 15.7. That is better, but still about three times the guideline.
Reading the Air Pollutant Index
The
Department of Environment reports air quality as the
Air Pollutant Index (API). A reading of 0 to 50 is good, 51 to 100 moderate, 101 to 200 unhealthy, 201 to 300 very unhealthy, and above 300 hazardous. PM2.5 was added to the index in 2018 and now usually sets the reading. Under current guidelines, schools must stop outdoor activities when the API passes 100, and close when it passes 200.
Transboundary haze
Most severe haze episodes come from forest and peatland fires, mostly in Indonesia, carried across by the wind during the dry season. 2026 was a bad year. On 31 August the station at Serian in Sarawak recorded an API of 475, and on 8 October, 38 of the country's 68 monitoring stations recorded unhealthy air, with Segamat in Johor highest at 187. Schools in Batu Pahat closed on 7 October after the API there passed 200. The ASEAN Agreement on Transboundary Haze Pollution, signed in 2002, commits member states to prevent and monitor fires, but haze keeps returning in dry years.
What cities can do
Cities cannot stop fires in another country, but they control their own emissions: cleaner public transport, less idling traffic, dust control on building sites, and an end to open burning. Trees trap some particles on their leaves, though only modestly. During haze, the priorities are clear warnings, clean indoor air in schools and clinics, and protecting people who must work outdoors.
Watch video: Air Quality and Haze
Key Insight: Malaysia's PM2.5 levels improved in 2025 but remain about three times the WHO guideline. The API sets clear thresholds: outdoor school activities stop above 100 and schools close above 200, as happened in parts of the country in October 2026.
Q: Above what API reading must schools in the affected area close?
Schools must stop outdoor activities for pupils when the API passes 100, and close when it passes 200. Readings of 101 to 200 count as unhealthy and 201 to 300 as very unhealthy.
How did the haze affect you, your family or your workplace this year? What would have helped most: earlier warnings, cleaner indoor air, or changes to outdoor work?
Mitigation vs Adaptation
There are two ways a city can respond to climate change, and it needs both.
Two kinds of action
Mitigation means reducing greenhouse gas emissions or increasing the sinks that absorb them. It tackles the cause. For cities this means cleaner energy, efficient buildings, public transport, walking and cycling, and less waste. Since Module 1 showed that urban areas account for 67 to 72% of global emissions, cities carry much of the mitigation task.
Adaptation, in the words of the
IPCC's Working Group II, is the process of adjusting to actual or expected climate and its effects, to reduce harm or take advantage of opportunities. It deals with the heat, floods and haze that are already happening or already locked in. Shade, cooling centres, bigger drains, flood warnings and raised buildings are all adaptation.
Why both are needed
Mitigation alone cannot protect people from the warming that past emissions have already caused. Adaptation alone becomes ever more expensive, and eventually impossible, if emissions keep rising. A city that only adapts is running to stand still.
Co-benefits
The best measures do both at once. A cool roof cuts the energy a building uses for cooling and lowers its indoor temperature. Shade trees on a bus route make walking to public transport bearable and encourage people to leave the car at home. Public transport reduces emissions and improves local air quality. Measures like these, with
co-benefits, deserve priority because each ringgit works twice.
Maladaptation
Some responses make things worse.
Maladaptation is action that increases risk or emissions, now or later, or shifts harm onto someone else. Relying on more air conditioning heats the street and adds emissions. A higher flood wall on one stretch of river can push water onto the neighbours downstream. A levee can encourage building on a floodplain that later floods worse when the defence is overtopped. Good adaptation asks who else is affected, and what happens when the design limit is exceeded.
In Kuala Lumpur
DBKL's Kuala Lumpur Climate Action Plan 2050 covers both sides, from low-carbon buildings and transport to flood and heat resilience.
Mitigation and Adaptation - With Co-Benefits in the Middle
Key Insight: Mitigation cuts emissions and tackles the cause. Adaptation copes with the heat, floods and haze already locked in. Measures with co-benefits, such as cool roofs and shade trees on transit routes, do both, while maladaptation shifts or raises the risk.
Q: Which of these is an example of maladaptation?
Relying on more air conditioning protects people indoors but heats the street outside and adds emissions, which raises the risk over time. The other options reduce heat or flooding without shifting the harm elsewhere.
Think of a climate measure in your town, such as a new drain, wall, cooling centre or bus lane. Is it mitigation, adaptation or both? Could it shift risk onto someone else?
Planning for Resilience
Resilience is the ability of a neighbourhood to prepare for, cope with and recover from shocks such as a heatwave, a flash flood or a haze episode. It starts with understanding risk.
Hazard, exposure and vulnerability
The IPCC describes climate risk as the result of three things interacting. A
hazard is the physical event, such as extreme heat, intense rain or smoke.
Exposure is the people, homes, services and infrastructure located where the hazard can strike.
Vulnerability is how easily they are harmed and how well they can cope. A flood in an empty field is a hazard with little exposure. The same flood in a street of ground-floor homes where older residents live alone is a high risk.
A step-by-step assessment
A council officer, a residents' association or a school can work through five steps.
First,
name the hazards. Which matter here: heat, flash floods, haze, landslips? Use MetMalaysia alerts, the Department of Irrigation and Drainage's
Public InfoBanjir portal for river levels and flood warnings, and the Department of Environment's API readings.
Second,
map the exposure. Mark the streets that flooded before, the hottest unshaded spots, and the homes, schools, clinics and roads in harm's way.
Third,
identify vulnerability. Who would struggle most: older people living alone, outdoor workers, families without air conditioning, people with disabilities, ground-floor homes, shops with stock at floor level?
Fourth,
choose actions that work on each part. Reduce the hazard with shade, cleaner drains and retention ponds. Reduce exposure by moving electrical equipment and stock above flood level, or by opening a cooling centre. Reduce vulnerability with a check-in list for vulnerable neighbours and warnings shared through a community chat group.
Fifth,
prioritise and review. Start with actions that are cheap, quick and protect the most vulnerable, then check after each storm or heatwave what worked.
Resilience at the community level
The PPR Beringin pilot in Kuala Lumpur shows the approach in practice: residents and the city mapped where heat hit hardest and then built shade and a cooling centre where it was most needed. The 13th Malaysia Plan includes community-based disaster preparedness among its flood targets, recognising that neighbours are often the first responders.
Climate Risk - Hazard, Exposure and Vulnerability, After the IPCC
Key Insight: Climate risk comes from a hazard meeting exposed and vulnerable people and places. A neighbourhood can assess its risk in five steps: name the hazards, map exposure, identify vulnerability, choose actions, and review after every event.
Q: In the IPCC framework, which three things combine to create climate risk?
Risk comes from a hazard, such as heat or intense rain, meeting exposure, the people and assets in the way, and vulnerability, how easily they are harmed. Reducing any one of the three lowers the risk.
Action step: sketch a quick risk map of your street or workplace. Mark one hazard, the people or places most exposed, and who is most vulnerable. What is the cheapest first action you could take?
Module 5: Resource Flows: Water, Waste, Energy and Food
Closing the loops of urban metabolism
How much water, waste, energy and food flow through Malaysian cities, where they are lost, and how leak control, recycling, efficient buildings, rooftop solar and urban farming close the loops.
Learning Objectives - Map a city's main resource flows and read them for losses
- Explain non-revenue water and the options for reducing and reusing water
- Apply the waste hierarchy and describe Malaysia's separation-at-source rules
- Describe how buildings use energy and how efficiency and rooftop solar cut it
- Evaluate what urban farming can and cannot supply
What You'll Learn - Malaysia's urban metabolism in four numbers
- Non-revenue water, rainwater harvesting and Singapore's NEWater
- Waste volumes, the recycling rate and Act 672
- The waste hierarchy, composting and biogas
- Buildings, cooling and green building ratings
- Solar ATAP and the Low Carbon Cities 2030 Challenge
- Community gardens in Kuala Lumpur, food self-sufficiency and Singapore's revised food targets
Mapping the Flows
Module 1 introduced urban metabolism: the idea that a city takes in water, food, energy and materials and sends out wastewater, rubbish, heat and emissions. This module puts numbers on those flows for Malaysia and asks where the loops can be closed.
Four flows in numbers
Water. Malaysians used about 225 litres of water per person per day at home in 2024, according to national figures cited by the Penang water utility PBAPP. Water services are regulated by the
National Water Services Commission (SPAN).
Waste. The Solid Waste Management and Public Cleansing Corporation (SWCorp) has estimated that the country generates about 39,000 tonnes of solid waste a day, or about 1.17 kg per person.
Energy. According to the Energy Commission, commercial users took 29% of the country's electricity in 2018 and households 20.5%, so buildings of one kind or another account for about half.
Food. The Department of Statistics' 2025 accounts show that Malaysia is self-sufficient in some vegetables but imports about 68% of its chilli, 59% of its round cabbage and 83% of its ginger.
Reading a flow map
Researchers often draw these flows as a
Sankey diagram, where arrows show each flow in and out and the width of each arrow shows its size. A flow map shows at a glance where the biggest flows are, where resources are lost along the way, and where an output from one system could become an input to another.
That last question is the heart of the
circular economy. Food waste can become compost for city gardens. Treated wastewater can be reused by industry. Rain falling on roofs can flush toilets. Each loop that closes means less drawn in from outside and less sent away as waste.
Where to start
A council does not need perfect data to begin. Rough figures for water bills, waste tonnage, electricity use in its own buildings and the share of food waste in household bins are enough to show where the largest flows and losses are. The rest of this module takes each flow in turn.
Urban Metabolism in Numbers - SPAN, SWCorp, Energy Commission and DOSM
Key Insight: Mapping water, waste, energy and food flows shows where resources are lost and where an output could become an input. Rough numbers are enough to start: about 225 litres of water and 1.17 kg of waste per person per day.
Q: Roughly how much solid waste does Malaysia generate each day?
SWCorp has estimated about 39,000 tonnes a day, or about 1.17 kg per person. Waste is one of the four main flows a city can map and reduce.
If you mapped your own household's flows for a month, which do you think would be largest compared with what you actually need: water, electricity, food or rubbish?
Water In, Water Out
Every litre from a tap has travelled a long way: from a forested catchment to a river or dam, through a treatment plant, along kilometres of pipe to a home, and then down the drain to a sewage plant and back to a river. Losses and pollution can occur at every step.
Non-revenue water
Non-revenue water (NRW) is treated water that is lost before it is billed, through leaking and burst pipes, theft and faulty meters. It is expensive, because every lost litre has already been pumped and treated. According to SPAN, NRW stood at 37.1% of treated water nationally in 2023, and SPAN reported 34.7% for Peninsular Malaysia and Labuan in mid-2025. In other words, roughly a third of the water the country treats never reaches a paying customer. SPAN's long-term target is below 25%. Getting there means finding leaks early, controlling pressure so that pipes burst less often, and replacing ageing mains.
Catching the rain
Malaysia receives heavy rainfall, yet most of it runs off roofs and into drains. Guidelines approved in 2011 under the Uniform Building By-Laws, and amended by-laws gazetted by states from 2012, require rainwater harvesting systems on bungalows and semi-detached houses with roofs of 100 square metres or more, and adoption and enforcement vary from state to state. Harvested rainwater can flush toilets, water gardens and wash cars. It also holds back a little runoff in a storm, linking water supply to the flood problem in Module 4.
Water used twice
Singapore shows how far reuse can go. Its
NEWater plants treat used water to a very high standard, mostly for industry, and can now supply up to 40% of the country's water demand. The national water agency plans to raise that to 55% by 2060. Treated water from homes is no longer a waste product but a reliable local source that does not depend on rain.
Protecting the source
In the Klang Valley, the weakest link is often upstream. Pollution incidents on rivers that feed treatment plants have repeatedly forced plants to shut, cutting supply to hundreds of thousands of homes. Protecting catchment forests and river reserves, and enforcing rules on factories upstream, is part of urban water security.
Watch video: Water In, Water Out
Key Insight: About a third of Malaysia's treated water is non-revenue water, lost before it is billed. Fixing leaks, harvesting rain and reusing treated water, as Singapore does with NEWater, all close the water loop.
Real-World Example: A housing estate in Shah Alam sees its water bills rise while usage stays flat. The water operator installs district meters and finds that one zone loses far more water overnight than its homes could use. A pressure-reducing valve and the repair of two leaking mains cut losses in that zone sharply.
Q: What is non-revenue water?
Non-revenue water is treated water lost through leaks, bursts, theft and faulty meters before it is billed. In Malaysia it is roughly a third of all treated water.
Action step: check your last water bill and estimate how many litres your household uses per person per day. How does it compare with the national figure of about 225 litres?
From Landfill to Circular
Most of Malaysia's rubbish still ends up in landfill. The minister for housing and local government put municipal solid waste at 15.2 million tonnes in 2024, and projects it to rise to about 17 million tonnes by 2035.
Recycling is rising, slowly
The national recycling rate rose from 35.4% in 2023 to 37.9% in 2024, short of the 40% target set for 2025. Since 1 September 2015,
separation at source under the Solid Waste and Public Cleansing Management Act 2007 (Act 672) has been mandatory for households in Kuala Lumpur, Putrajaya, Johor, Negeri Sembilan, Melaka, Pahang, Perlis and Kedah. Households sort recyclables into paper, plastic and other recyclables, which are collected once a week, while other waste is collected twice a week. Compounds for failing to separate began in 2016. States that did not adopt Act 672 run their own systems.
The food waste problem
Food is the largest single part of household rubbish. The housing and local government minister told the Dewan Rakyat in October 2026 that food makes up nearly 40% of the roughly 40,000 tonnes of solid waste generated each day, or about 16,000 tonnes. Estimates of its share range from about a third of domestic waste in SWCorp data to nearly half of all solid waste in earlier ministry figures, because they cover different streams and years. In landfill, food waste rots and releases methane, a powerful greenhouse gas, and it contaminates recyclables in mixed bins.
The waste hierarchy
The
waste hierarchy ranks the options. The best is to
reduce waste in the first place, for example by buying and cooking only what is needed. Next is
reuse, then
recycling and composting, then
recovering energy, and last of all
disposal in landfill. Food waste can be composted, or broken down in sealed tanks without oxygen through
anaerobic digestion, which produces biogas for energy and a fertiliser by-product. Burning mixed waste to make electricity sits low on the hierarchy, because it destroys materials that could have been recovered.
What a city can do
The most effective city programmes make the right choice the easy one: separate bins that are collected reliably, food waste collection from markets and food courts, repair and reuse centres, and clear rules on single-use packaging. The house crows of Module 3 are a reminder that badly managed waste affects wildlife and health as well as landfill space.
The Waste Hierarchy - From Reduce to Disposal
Watch video: From Landfill to Circular
Key Insight: Malaysia recycled 37.9% of its waste in 2024, below the 40% target. The waste hierarchy puts reducing and reusing first and landfill last, and food waste, the largest part of household rubbish, is best composted or digested.
Q: Into which categories must households in Act 672 states separate their recyclables?
Households sort recyclables into paper, plastic and other recyclables, collected once a week, while the rest of their waste is collected twice a week.
Which step of the waste hierarchy could your household or workplace move up next: reducing, reusing, or separating food waste from the rest?
Energy and Low-Carbon Buildings
Buildings are where most city energy is used. In 2018, according to the Energy Commission, commercial users accounted for 29% of Malaysia's electricity and households for 20.5%. In a tropical climate, the largest single use in most buildings is
cooling.
Efficiency first
The cheapest energy is the energy a building never needs. Passive design from Module 4, such as shading windows, reflective roofs, insulation and cross-ventilation, cuts the heat that air conditioning has to remove. Efficient air conditioners, LED lighting, sensors that switch off lights and cooling in empty rooms, and simply setting thermostats a degree or two higher, cut use further.
Rating green buildings
The
Green Building Index, launched in 2009 by Malaysia's architects' and consulting engineers' associations, rates new and existing buildings on energy and water efficiency, indoor environment, materials and site planning. Ratings help buyers and tenants compare buildings and give developers a goal to design for. A rating at handover only matters, though, if the building is run well afterwards.
Rooftop solar
Roofs are also power stations in waiting. Malaysia's Net Energy Metering scheme closed in June 2025, and since 1 January 2026 rooftop solar in Peninsular Malaysia has been supported through
Solar ATAP. Capacity is allocated first come, first served, within limits the government sets, and the scheme favours using solar power on site: electricity exported to the grid earns bill credits below the full tariff, at the energy charge for households and the average system marginal price for businesses. By 30 April 2026, government rooftop and small solar programmes had added 3,254.61 MW, of which 2,903 MW came from net metering, 345 MW from the older feed-in tariff, and 6.61 MW from Solar ATAP in its first four months.
Low carbon cities
At city scale, the
Low Carbon Cities 2030 Challenge, launched in 2019 under the Low Carbon Cities Framework, encourages local authorities, universities and companies to cut emissions and recognises them by how much they achieve. The natural resources ministry aims to establish 200 low carbon zones by 2030, and by early 2026, 146 of 156 local authorities had been trained, with 70 already implementing low-carbon measures. An audit by the Malaysian Green Technology and Climate Change Corporation found that low carbon city initiatives cut emissions by about 324,000 tonnes of carbon dioxide equivalent in 2025.
Key Insight: Commercial and household users consume about half of Malaysia's electricity, much of it for cooling. Passive design and efficiency come first, then rooftop solar, now supported through Solar ATAP since January 2026.
Real-World Example: A council in Melaka audits its own buildings and finds that its main office runs air conditioning in empty meeting rooms at weekends. Timers and occupancy sensors, a thermostat setting of 25°C and LED lighting cut the building's electricity bill noticeably. The council then installs solar panels on the roof to supply its daytime load.
Q: Roughly what share of Malaysia's electricity did commercial and household users consume in 2018?
Commercial users took 29% and households 20.5%, about half in total. Industry took most of the rest. Cooling is the largest single use in most tropical buildings.
Look at the building where you spend most of your working day. What is the single biggest waste of energy you can see, and who could fix it?
Growing Food in the City
Cities depend on food grown elsewhere, often in other countries. Urban farming cannot change that, but it can do more than its small harvests suggest.
What Malaysia grows and imports
The Department of Statistics' 2025 supply accounts show 23 agricultural commodities above 100% self-sufficiency, including French beans and tomatoes. But Malaysia still imports about 83% of its ginger, 68% of its chilli and 59% of its round cabbage. Disruptions to trade or bad harvests abroad show up quickly in market prices.
Community gardens in Kuala Lumpur
Kuala Lumpur City Hall's Local Agenda 21 programme began supporting community gardens in 2016, and by 2023 the mayor cited 40 community farming projects across the city. DBKL now has an urban farming unit that runs courses and helps residents start gardens on unused land. Gardens such as the TTDI Edible Community Garden grow vegetables and herbs, run composting from household food waste, and give neighbours a reason to meet.
What city farms can and cannot do
City farms are best suited to fresh, perishable foods that lose value in transport, such as leafy greens, herbs, chillies and mushrooms. They cannot replace the large areas of farmland needed for rice and other staples. Their wider value lies in fresher food, education, community ties, cooling green space, habitat for pollinators, and a home for compost made from city food waste.
The limits of high-tech farming
Indoor vertical farms stack crops under artificial light. They save land and water, but lighting and cooling use a great deal of electricity, and many have closed around the world because their costs were too high. Singapore learned this the hard way. In November 2025 it dropped its goal of producing 30% of its nutritional needs locally by 2030, citing land constraints and high labour and energy costs. Its new targets for 2035 are narrower: to raise local production of fibre, such as leafy vegetables, beansprouts and mushrooms, from about 8% to 20% of what is eaten, and of protein, such as eggs and seafood, from about 26% to 30%.
The lesson for Malaysian cities is to treat urban farming as one part of a food system: valuable for fresh produce and for community, but alongside, not instead of, protecting farmland and keeping supply chains resilient.
Watch video: Growing Food in the City
Key Insight: Urban farms suit fresh, perishable crops and bring community, compost and green space, but cannot replace farmland for staples. Singapore dropped its 30 by 30 goal in 2025 over high land, labour and energy costs.
Q: Why did Singapore drop its "30 by 30" food goal in November 2025?
The government cited land constraints and high labour and energy costs. It replaced the goal with narrower 2035 targets for fibre and protein.
Is there an unused patch of land near you that could become a community garden? What would residents need to get it started and keep it going?
Module 6: Land, Housing and Density
How a city uses land decides how much nature it keeps
Why cities spread faster than they grow, the 2026 global housing crisis and Malaysia's affordability gap, how informal settlements can be upgraded rather than cleared, building around rail stations and the 15-minute city, and how to green a neighbourhood without pricing its residents out.
Learning Objectives - Compare sprawl with compact growth by their cost to land, nature and travel
- Explain the housing crisis in SDG 11 terms and describe Malaysia's affordability gap
- Explain why informal settlements form and why upgrading usually beats eviction
- Evaluate transit-oriented development and the 15-minute city, including their critics
- Recognise green gentrification and name tools that share the benefits of greening
What You'll Learn - Sprawl, compact growth and SDG indicator 11.3.1
- The SDG 11 Global Report 2026 and the Baku Call to Action
- House prices, incomes and unsold homes in Malaysia
- Squatter colonies and water villages in Sabah
- Baan Mankong in Thailand and incremental housing in Chile
- The Shah Alam Line, station-area housing and the TOD Standard
- The 15-minute city, its critics and green gentrification
Sprawl or Compact Growth?
Every new home needs land. Whether a city grows outward onto farms and forest, or upward and inward on land it already uses, is one of the biggest ecological choices it makes.
What sprawl means
Sprawl is low-density growth at the edge of a city, usually in separate zones for homes, shops and offices, linked mainly by roads. Each household uses more land, more road and more pipe, and most trips need a car.
Compact growth builds at higher density, mixes homes with jobs and services, and links them by walking, cycling and public transport.
The ecological cost
A widely cited study by Karen Seto and colleagues in 2012 forecast that if past trends continued, the world's urban land could grow by about 1.2 million square kilometres by 2030, nearly tripling its extent in 2000. Much of the fastest growth was forecast in biodiversity hotspots, including the Western Ghats and Sri Lanka and the forests of West Africa. Researchers behind the Atlas of Urban Expansion have also found that urban densities in most of the world have been falling, so cities have spread faster than their populations have grown.
The UN tracks this with
SDG indicator 11.3.1, the ratio of the rate at which a city consumes land to the rate at which its population grows. A value above 1 means land is being used up faster than people are arriving. The SDG 11 Global Report 2026 found that across 123 countries, land consumption has become more closely aligned with population growth, which is progress, but not yet a reversal.
Density has trade-offs
Compact is not automatically better. Very dense districts with little shade or open space can be hot, crowded and short of green, as Modules 2 and 4 showed. The aim is density done well: enough people to support frequent transit and local shops, with parks, trees and drainage built in from the start. Ecologists sometimes describe this as
land sparing, building compactly so that larger areas of habitat elsewhere can stay intact.
Sprawl and Compact Growth Compared
Key Insight: Sprawl uses more land, road and pipe per household and makes most trips depend on cars. Compact growth spares land for nature, but only works well when parks, shade and drainage are built in.
Q: What does a value above 1 for SDG indicator 11.3.1 mean?
Indicator 11.3.1 divides the land consumption rate by the population growth rate. Above 1 means the city is spreading faster than it is gaining people.
Think of the newest housing area you know on the edge of your town. What was on that land before, and how do most residents get to work and school?
The Housing Crisis
Housing is the 2026 headline for SDG 11. UN-Habitat's
SDG 11 Global Report 2026, launched in New York on 9 July 2026, put housing at the centre of sustainable cities. Where homes are unaffordable, insecure or far from jobs and services, the report argues, progress on transport, public space, disaster risk and health is held back too.
The global numbers
The report found that at least 3 billion people live in inadequate housing. More than 1.16 billion lived in slums and informal settlements in 2024, a number that has risen by more than 130 million since 2015. Nearly half of all households spend more than 30% of their income on rent, the usual line beyond which housing is considered unaffordable.
Two months earlier, the thirteenth World Urban Forum met in Baku, Azerbaijan, from 17 to 22 May 2026 on the theme of housing. UN-Habitat reported more than 57,000 participants from 176 countries. The forum closed with the
Baku Call to Action, a stakeholder-led document that asks governments for affordable, climate-resilient housing, secure tenure, serviced land, the upgrading of informal settlements and protection against forced eviction.
Why housing is an ecology issue
When homes near jobs are too expensive, families move to the cheaper fringe. That means more land cleared, longer commutes, more cars and more emissions. Affordable homes in well-connected places are one of the strongest tools against sprawl.
Malaysia's affordability gap
A common measure is the
median multiple: the median house price divided by the median annual household income. A multiple of 3 or less is usually treated as affordable. In 2015 the Khazanah Research Institute put Kuala Lumpur at 5.4 and Penang at 5.2, and in 2019 it reported that Malaysia's national multiple had been above 3 since 2002.
Yet unsold homes sit empty. The Dewan Rakyat was told in June 2026 that 32,800 completed homes worth about RM16.4 billion were unsold in the first quarter of 2026, and that 46.9% of them were priced at RM300,000 or less. Price is only part of affordability. Location, size, design and the cost of getting to work matter as well. The 13th Malaysia Plan targets one million affordable homes between 2026 and 2035.
Key Insight: At least 3 billion people live in inadequate housing, and nearly half of households worldwide spend more than 30% of income on rent. In Malaysia, house prices have run above three times median income for two decades, while thousands of completed homes go unsold.
Real-World Example: A young couple both work in central Kuala Lumpur. The homes they can afford are 40 km away, with no rail line nearby. They buy a second car and spend nearly three hours a day in traffic. A smaller flat near an MRT station would cost more to buy but less to live in once transport is counted.
Q: According to the SDG 11 Global Report 2026, roughly how many people live in inadequate housing?
The report found that at least 3 billion people live in inadequate housing, with more than 1.16 billion of them in slums and informal settlements.
What share of your household's income goes on rent or a housing loan, plus the cost of getting to work? Would you count your home as affordable once travel is included?
Informal Settlements
An
informal settlement is housing built without legal title or planning permission, often on land nobody else wanted: riverbanks, steep slopes, road reserves or the sea. UN-Habitat counts a household as living in a slum if it lacks one or more of five things: durable housing, enough living space, safe water, adequate sanitation and secure tenure.
Why they form
Informal settlements grow when people arrive faster than affordable, legal housing is built. They are usually close to work, markets and schools, which is why residents stay even when conditions are poor. Because they occupy risky land, they are often the first places hit by floods, landslides and fire.
The Malaysian picture
In the early 2000s Selangor set a target of zero squatters by 2005 and moved most families into low-cost high-rise flats. The deadline was missed, and critics said too few replacement homes had been built in time. Today the problem is most visible in Sabah. The state government told its assembly in December 2025 that squatter colonies had fallen from 285 in 2023 to 233, and that it proposed to gazette 45 of them as villages so they can be planned and serviced.
Many are water villages built on stilts over the sea. On 19 April 2026, Bernama reported that about 1,000 houses were destroyed when fire swept through the water village of Kampung Bahagia in Sandakan. Tightly packed timber homes and low tide, which left firefighters short of water, let the blaze cover more than four hectares.
Upgrading rather than eviction
Clearing a settlement destroys homes and networks that people spent years building, and often moves them far from work.
In-situ upgrading improves the settlement where it stands: secure tenure, paths, drains, water, sanitation, fire breaks and stronger homes. Thailand's
Baan Mankong programme, launched in 2003, gives community groups grants for infrastructure and loans for housing, and lets them plan the upgrade themselves. By 2014 it had reached more than 96,000 households in about 1,800 communities. In Iquique, Chile, the architects Elemental used a subsidy of about US$7,500 per family to build "half of a good house" that families have since extended themselves.
Watch video: Informal Settlements
Key Insight: Informal settlements form when people arrive faster than affordable legal housing is built, and they often sit on the riskiest land. Upgrading in place, with secure tenure and basic services, usually works better than eviction.
Q: Which of these is one of UN-Habitat's five criteria for a slum household?
A household counts as living in a slum if it lacks durable housing, enough living space, safe water, adequate sanitation or secure tenure.
If your neighbourhood had to be upgraded, which three improvements would residents most want first, and who should decide the order?
Building Around Transit
Transit-oriented development (TOD) puts homes, jobs and services within an easy walk of a rail or bus station, so that people can live well without driving everywhere. The
TOD Standard from the Institute for Transportation and Development Policy sums it up in eight principles: walk, cycle, connect, transit, mix, densify, compact and shift.
TOD in the Klang Valley
The
Shah Alam Line, also known as LRT3, opened to the public on 29 June 2026. It runs 37.8 km from Bandar Utama to Johan Setia with 20 stations, and Prasarana is targeting 67,000 passengers a day in its first year. At its launch the Transport Minister said large park-and-ride sites at Sri Andalas, Kayu Ara, Johan Setia and Bandar Bukit Tinggi could be redeveloped for affordable housing and mixed use, and the Prime Minister said the priority must be affordable homes, not luxury ones. No project had been finalised. In Cheras, MRT Corp and IJM Land unveiled The Linque in June 2026, about 586 serviced apartments above Cochrane station, MRT Corp's first TOD in the Klang Valley.
A station alone does not create TOD. Many Malaysian stations are surrounded by car parks, highways and long walks in the heat. Shaded, safe walking routes to the station matter as much as the buildings beside it.
The 15-minute city
The
15-minute city, developed by Carlos Moreno and taken up in Paris, aims for daily needs such as work, school, shops, health care and parks to be within a 15-minute walk or bike ride of home. Since 2020 Paris has calmed traffic outside more than 300 schools and made about 100 of those streets permanently car-free.
The critics
In 2023 the idea became the target of conspiracy theories claiming that residents would be confined to their districts. In Oxford, which was introducing camera-enforced traffic filters, the council explained that drivers could still reach every part of the city. There are also serious criticisms. Poorer districts may have fewer services to start with, and new amenities can raise rents, so the benefits can go to newcomers rather than existing residents.
The TOD Standard - Eight Principles (ITDP)
Watch video: Building Around Transit
Key Insight: Transit-oriented development puts homes, jobs and services within an easy walk of frequent transit. The Shah Alam Line opened in June 2026, and the government is studying affordable housing on its park-and-ride sites.
Q: What is the main aim of the 15-minute city?
The idea is that work, school, shops, health care and parks should be within a 15-minute walk or ride. It adds choices close to home and does not restrict travel.
Walk from your home to the nearest rail or bus station. Is the route shaded, safe and direct? What one change would make it easier for your neighbours to leave the car at home?
Green Gentrification
A new park, a cleaned-up river or a tree-lined street makes a neighbourhood healthier and more pleasant. It can also make it more expensive. When rising rents and property prices push out the people the greening was meant to help, researchers call it
green gentrification.
The evidence
Much of the research comes from a team in Barcelona led by Isabelle Anguelovski. A study of 18 parks and gardens created in Barcelona in the 1990s and early 2000s found that some of the surrounding areas saw house prices rise and lower-income residents replaced by wealthier newcomers. A wider project on greening in North American and European cities found a link between greening and gentrification in many of the cities studied. The researchers are careful to say that much of the evidence is case-based, and that greening is hard to separate from the other forces that push up prices.
The same risk applies to transit. In 2026 a town planner at Universiti Teknologi MARA warned that land around Shah Alam Line stations becomes a target for speculation once a line is announced, pricing out lower-income households. She called for enforceable measures such as affordable housing quotas, income-based eligibility and legally binding affordable units within station catchments.
Tools to share the benefit
Just green enough. The geographers Winifred Curran and Trina Hamilton coined this phrase in 2012, and a 2014 review by Jennifer Wolch, Jason Byrne and Joshua Newell took it up. It means greening shaped by what existing residents ask for, such as safe play space or a cleaned-up drain, rather than a flagship park designed to attract newcomers.
Community land trusts. A non-profit trust owns the land and keeps the homes on it affordable for good. In Washington, DC, the team behind the planned 11th Street Bridge Park drew up an equitable development plan before building began, and the Douglass Community Land Trust was set up in 2019 to keep housing near the park within residents' reach.
Rules and agreements. Inclusionary housing quotas, protection for tenants, local hiring and community benefit agreements all help existing residents share in the gains.
Many small projects. Spreading greening across many neighbourhoods, rather than concentrating it in one showpiece, makes it less likely that any single area becomes a target for speculation.
Watch video: Green Gentrification
Key Insight: Greening and new transit can raise rents and push out the people they were meant to help. Planning for affordability from the start, through "just green enough" design, community land trusts and affordable housing quotas, helps existing residents share the benefit.
Real-World Example: A council plans to turn a concrete monsoon drain behind a row of low-cost flats into a landscaped river walk. Before work starts, it meets residents, who ask for shade, a playground and safe lighting. The council also agrees with the state housing agency that the nearby flats will stay at controlled rents for 15 years after the project opens.
Q: What does a community land trust do to limit displacement?
A non-profit trust holds the land and controls resale prices or rents, so the homes on it stay affordable even when the area around them becomes more expensive.
Is there a park, river or rail project planned near you? Who is likely to benefit most once it is finished, and what could be done now to make sure existing residents are among them?
Module 7: Governance, Finance and Community Action
Who decides, who pays, and what you can do
Who carries the burden of pollution, heat and floods, how Malaysia's planning system works and where the public can object, how cities pay for nature, the data tools anyone can use, how residents get heard, and a 90-day plan for your own neighbourhood.
Learning Objectives - Explain environmental justice and recognise who carries the heaviest environmental burdens
- Describe Malaysia's hierarchy of development plans and where the public can object
- Identify ways to finance urban nature, from council budgets to green bonds and disclosure
- Use satellite data, canopy maps and citizen science to make the case for change
- Build and run a 90-day action plan for one problem in your neighbourhood
What You'll Learn - Environmental justice and the Sungai Kim Kim pollution of 2019
- Act 172 and the hierarchy of national, structure and local plans
- Objection windows, local councils and the National Climate Change Bill
- Assessment tax, biodiversity net gain, green bonds and sukuk
- TNFD and Malaysia's National Sustainability Reporting Framework
- Heat maps, canopy maps, the City Nature Challenge and the Virtual Island of Penang
- Taman Rimba Kiara and the ladder of participation
- A 90-day neighbourhood plan
Environmental Justice
Earlier modules showed that heat, floods, haze and polluted rivers do not fall evenly across a city.
Environmental justice asks who carries those burdens, who gets the benefits of parks, trees and clean air, and who has a say in the decisions.
Where the idea came from
The modern movement grew out of protests in the United States in the 1980s, when residents of mostly Black and low-income communities objected to toxic waste sites being placed near their homes. Researchers then showed that polluting facilities were concentrated in poorer and minority neighbourhoods far more often than chance would explain.
The pattern persists in the urban landscape. A 2020 study by Jeremy Hoffman, Vivek Shandas and Nicholas Pendleton looked at 108 urban areas in the United States. Neighbourhoods that had been "redlined" in the 1930s, marked as risky for lending largely because of who lived there, were on average about 2.6°C hotter at the surface than other areas, with less tree cover and more paving.
Three kinds of justice
Scholars usually describe three dimensions.
Distributive justice is about who gets the burdens and the benefits.
Procedural justice is about who takes part in decisions and how fairly they are made.
Recognition is about whose knowledge, culture and needs are respected in the first place.
A Malaysian case
In March 2019, chemical waste was illegally dumped into Sungai Kim Kim in Pasir Gudang, Johor, an industrial town where homes and schools sit close to factories. Toxic fumes made thousands of people ill. By 14 March, 2,775 people had received treatment, and 111 schools in Pasir Gudang were closed. In 2023 a lorry driver was fined RM100,000 and the company that employed him RM320,000. The case showed how residents living beside industry can carry the risk of other people's waste.
Asking the justice question
For any plan or project, it helps to ask three questions. Who gains? Who pays, in health, money or lost space? Who was asked? A park, a flood scheme or a new road can pass every technical test and still fail this one.
Watch video: Environmental Justice
Key Insight: Environmental justice asks who carries the burdens of pollution, heat and floods, who gets the benefits of green space, and who has a say. The 2019 Sungai Kim Kim pollution showed how communities beside industry carry the risk.
Q: Which dimension of environmental justice is about who takes part in decisions?
Procedural justice is about how fairly decisions are made and who takes part. Distributive justice is about who gets the burdens and benefits, and recognition is about whose needs and knowledge are respected.
Think of the nearest landfill, highway, factory or flood-prone low-lying area to where you live. Who lives closest to it, and who decided it would go there?
How Malaysia Plans Its Cities
Most of what this course has covered, from tree cover to flood plains to housing density, is decided through development plans. Knowing how they work is the first step to influencing them.
The law and the hierarchy
In Peninsular Malaysia, planning is governed by the
Town and Country Planning Act 1976 (Act 172). Kuala Lumpur has its own law, the Federal Territory (Planning) Act 1982, and Sabah and Sarawak have their own planning laws. Plans form a hierarchy, each one guiding the next.
National Physical Plan. Sets the national spatial strategy. The fifth plan was approved by the National Physical Planning Council in October 2026, and the plan is reviewed every five years.
State structure plans. Set out policies for each state's development, such as growth areas and environmentally sensitive areas.
Local plans. Prepared by local councils, they map land use, density and open space plot by plot.
Special area plans can add detail for particular places, such as a historic core or a river corridor.
Individual projects then need
planning permission from the local planning authority, which must take the plans into account.
Where the public comes in
The best moment to influence a plan is while it is still a draft. Under Act 172, a draft local plan must be put on public display for at least four weeks, a period the council can extend once by up to four more weeks, during which anyone can send in objections and suggestions. The council may then hold a hearing before a committee of three people appointed by the State Planning Committee. Councils must also publicise a plan before they start preparing it, which is an even earlier chance to be heard. When Penang Island's draft local plan was displayed from October 2022 to January 2023, the city council received more than 1,500 submissions, and the state later decided to redraw the plan.
Councils and climate law
In the states, local councillors are appointed by the state government, and Kuala Lumpur is run by an appointed mayor. Local elections were suspended in the 1960s, and the debate about bringing them back revived in 2026. At national level, the government said in October 2026 that it aimed to table the
National Climate Change Bill in the current sitting of Parliament once the Cabinet approved it. The bill would set a legal framework for cutting emissions, adapting to climate change and measuring and reporting greenhouse gases.
Malaysia's Planning Hierarchy under Act 172
Key Insight: Malaysian planning runs from the National Physical Plan through state structure plans to local plans and individual planning permissions. The best time to influence a plan is when a draft is on public display.
Q: When is the best time for residents to influence a local plan?
A draft local plan must be displayed for public objections and suggestions for at least four weeks. Once a plan is approved, changing it is much harder.
Find out when your local council's local plan was last approved and when it is due for review. Where would you look, and whom would you ask?
Paying for Nature
Parks, street trees, wetlands and restored rivers need money to create and, just as important, to maintain. Knowing where that money can come from helps residents ask for realistic things.
Council budgets
Malaysian local councils depend heavily on
assessment tax (cukai taksiran), a tax on property paid by owners. Studies of council finances have found that it makes up more than half of their own revenue. Maintenance of parks, drains and trees competes with every other service for that money, which is why a new park without a maintenance budget can quickly decline.
Developers
Planning conditions can require developers to provide open space, drainage and community facilities as part of a project. Some countries go further. Since 12 February 2024, most major developments in England must deliver at least a 10%
biodiversity net gain, measured against the site before work began, and most of the habitat created must be maintained for at least 30 years.
Bonds and sukuk
A
green bond raises money from investors for projects with environmental benefits, such as flood defences, clean transport or efficient buildings. In 2014 Johannesburg issued a R1.46 billion green bond, the first municipal green bond listed on the Johannesburg Stock Exchange. Islamic finance offers the equivalent in
green and sustainability sukuk. In April 2021 Malaysia raised US$1.3 billion through what the Ministry of Finance described as the world's first US dollar sustainability sukuk issued by a government, with proceeds going to green and social projects.
Disclosure
Companies are increasingly asked to report how they depend on and affect nature. The
Taskforce on Nature-related Financial Disclosures (TNFD) published its final recommendations in September 2023. Malaysia launched its
National Sustainability Reporting Framework in September 2024, based on the international IFRS S1 and S2 standards, and the largest listed companies report under it for financial years starting in 2025. Disclosure does not pay for a park by itself, but it gives companies a reason to invest in the nature around their sites.
Making the case
Module 2 showed how to count ecosystem services. Putting a value on avoided flood damage, lower cooling bills or fewer heat illnesses turns greening from a cost into an investment that a council or company can justify.
Watch video: Paying for Nature
Key Insight: Urban nature is paid for through council budgets, developer obligations, green bonds and sukuk, and increasingly through corporate disclosure. A new park needs a maintenance budget as much as a construction budget.
Real-World Example: A residents' association wants its neglected pocket park restored. Instead of only asking the council for money, it brings a plan: the developer building next door will fund new planting as a planning condition, a nearby company will sponsor maintenance for three years under its sustainability programme, and residents will run a monthly clean-up. The council agrees, because its own share is small.
Q: What does England's biodiversity net gain rule require of most major developments?
Since February 2024, most major developments in England must leave biodiversity at least 10% higher than before, and maintain most of the habitat created for at least 30 years.
If you wanted a neglected green space near you restored, who besides the council could help pay for it, and what would they get in return?
Data and Tools
A complaint becomes much harder to ignore when it comes with evidence. Many of the tools that professionals use are now free or cheap enough for residents to use too.
Satellites
Since 2008, the whole archive of the US Landsat satellites has been free to download. Their thermal sensors measure how hot the ground surface is, which is how heat maps of cities like those in Module 4 are made. Europe's Sentinel-2 satellites photograph the land every few days at 10-metre detail, enough to see changes in tree cover, new clearing or flooded areas. Free online viewers let anyone compare images from different years.
Canopy and tree tools
Canopy maps show what share of each neighbourhood is shaded by trees, the measure behind the "30" in the 3-30-300 rule from Module 2. The free i-Tree tools from the US Forest Service estimate the benefits of individual trees and whole urban forests, such as stormwater held back and air pollution removed.
Citizen science
Citizen science means members of the public collecting data that researchers and planners can use. In the City Nature Challenge, cities around the world work together over four days to record as many wild species as they can using the iNaturalist app, whose community helps identify each photo. In 2026, organisers counted more than 3 million observations from over 106,000 people in 754 cities across 61 countries. The Klang Valley has taken part since 2018. Records like these can show a council that a "vacant" plot is in fact full of life.
Digital twins
A
digital twin is a live, three-dimensional computer model of a city, linked to real data, in which planners can test changes before making them. In October 2025, the Penang Island City Council launched the
Virtual Island of Penang, which maps the island's buildings, roads and trees, has an online module that checks submitted building plans against council guidelines, and monitors weather, soil and slope movement to warn of landslides. Kuala Lumpur City Hall has said it is planning a similar system.
Using data well
Data has limits. Satellites measure surface temperature, not the air people breathe. App records cluster where people walk. Good evidence combines several sources with what residents see every day.
Key Insight: Free satellite images, canopy maps, tree calculators and citizen science apps let residents gather the same kind of evidence as professionals. Digital twins such as the Virtual Island of Penang let councils test changes before making them.
Q: What do Landsat thermal sensors measure that makes them useful for heat maps?
Thermal sensors measure land surface temperature, which shows which roofs, roads and neighbourhoods heat up most. It is not the same as air temperature, so it should be read alongside other data.
Which free tool from this section could you use this month to gather evidence about one problem in your area, and what question would you try to answer with it?
Community Participation
Plans and budgets are made by officials, but they respond to people who turn up, organise and bring evidence. Malaysia has real examples of residents changing the outcome.
How much say?
In 1969 the American planner Sherry Arnstein described a
ladder of citizen participation with eight rungs. At the bottom are manipulation and therapy, where people are managed rather than heard. In the middle are informing, consultation and placation, where people can speak but power stays with officials. At the top are partnership, delegated power and citizen control. A useful test of any public engagement is to ask which rung it really sits on.
Taman Rimba Kiara
Taman Rimba Kiara is a green space in Taman Tun Dr Ismail, Kuala Lumpur. In 2017 a development order was issued for a high-rise project on part of it. Residents organised, documented the park's value and went to court. In January 2021 the Court of Appeal quashed the development order and held that the residents' association had the standing to challenge it. In April 2023 the Federal Court upheld that decision, ruling the order void because of the mayor's conflict of interest and because it contravened the Kuala Lumpur Structure Plan 2020.
Not every issue needs a court case. Most change comes from steadier work.
Ways to be heard
Residents' associations and joint management bodies give a neighbourhood one voice when dealing with the council.
Objections to draft plans during the public display period, as Section 7.2 described, carry legal weight.
Councillors and elected representatives can raise issues at council meetings and in the state assembly.
Programmes such as Local Agenda 21, which Kuala Lumpur City Hall uses to support community gardens, offer partnership with the council.
Participatory budgeting, pioneered in Porto Alegre, Brazil, from 1989, lets residents decide directly how part of a public budget is spent.
What makes a group effective
Groups that succeed tend to have a clear and specific ask, evidence, allies beyond the usual few, and patience. They also offer something themselves, such as volunteers for maintenance or local knowledge the council lacks.
Watch video: Community Participation
Key Insight: Residents can influence their city through associations, objections to draft plans, councillors, partnership programmes and, as Taman Rimba Kiara showed, the courts. Effective groups bring a clear ask, evidence and allies.
Q: What did the Federal Court decide about Taman Rimba Kiara in April 2023?
The Federal Court upheld the Court of Appeal's 2021 decision, finding the development order void because of the mayor's conflict of interest and because it contravened the Kuala Lumpur Structure Plan 2020.
Think of the last public consultation you saw or took part in. Which rung of Arnstein's ladder did it really reach, and what would have moved it one rung higher?
Your 90-Day Neighbourhood Plan
This course ends with action. A 90-day plan is long enough to achieve something real and short enough to keep a group motivated. The aim is not to fix your whole city, but to make one visible improvement and learn how change happens where you live.
Days 1 to 30: pick and measure
Choose
one problem that matters to neighbours and that you can see: a street with no shade, a drain that floods, a park nobody maintains, a missing footpath to the station. Then measure it, using the tools from this course. Count trees and estimate canopy (Module 2). Map where water pools after rain (Module 4). Record wildlife on iNaturalist (Module 3). Take dated photographs. Write down the baseline, because you will need it at the end.
Days 31 to 60: find allies and options
Find out who is responsible: the council department, the councillor, the land owner, the residents' association. Look up what the local plan says about the site. Talk to neighbours, schools, mosques, temples, churches and local businesses. Then draw up two or three options, from the cheapest quick fix to the ideal, with a rough cost for each and who might pay (Section 7.3). Ask the justice questions from Section 7.1: who gains, who pays and who has been asked.
Days 61 to 90: propose and track
Put a short written proposal to the decision-maker: the problem, your evidence, the options and what your group will contribute. Ask for a specific decision by a specific date. Agree what will be measured, and check it against your baseline. Share progress with neighbours, and record what worked and what did not.
After 90 days
Whether or not you got everything you asked for, you will have evidence, allies and a relationship with the people who decide. That is the foundation for the next project, and the way neighbourhoods become cooler, greener and fairer one step at a time.
The 90-Day Neighbourhood Plan
Key Insight: A 90-day plan picks one visible problem, measures it, builds allies and options, and puts a specific, evidence-based proposal to the people who decide. Measuring the baseline at the start is what lets you show progress at the end.
Q: Why should a 90-day plan record a baseline in the first 30 days?
Without a starting measurement, such as tree numbers, flood spots or photographs, a group cannot show what changed. The baseline is what turns effort into evidence.
Action step: write down the one problem you would choose for your own 90-day plan, the first measurement you would take, and two people you would ask to join you.
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Disclaimer: This course is for general educational and illustrative purposes only. It does not constitute professional medical, legal, or financial advice. Always consult a qualified professional for specific guidance.
