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| Query: | 9 |
| Theme: | Technologies for Responding to Urban Heat in Asia-Pacific |
| Posted: | 27th March 2026 |
| Closed: | 29th May 2026 |
| Raised by: | Dr. (Ar.) Sujata Kodag, President, Eco-Logic-Foundation, India and Md Selim Reza, System Analyst, Ministry of Finance, Bangladesh |
| Responses: | 20 |
Urban heat is becoming a major challenge in rapidly growing cities, particularly in developing countries where urban expansion is often unplanned.
We request community members to share perspectives that bring together both technology-driven and policy-oriented solutions. Some key areas that may be useful to explore include:
- What are the most effective tech solutions (like geospatial data, IoT sensors, AI, etc.) cities are using today to understand and reduce urban heat?
- How can cities practically scale green solutions (like urban forests, green roofs) and cool materials in dense, fast-growing areas?
- What kind of planning frameworks, digital tools, and policies — including financing mechanisms — are needed to make these solutions work on the ground, especially in resource-constrained settings?
The Query on Technologies for Responding to Urban Heat in Asia Pacific addressed three critical questions: what technologies are working for heat diagnosis and reduction; how green and cool solutions can be scaled beyond pilots to reach the most disadvantaged; and what governance and financing mechanisms need to be in place for interventions to work on the ground.
The most important point of agreement was that no single technology is sufficient — only integrated approaches will work. Satellite-derived Land Surface Temperature (LST) data from Landsat, ECOSTRESS, and Sentinel-3 gives planners a city-scale heat island map. GIS-based spatial analysis allows them to overlay this with population and building density data to identify where thermal exposure and social vulnerability intersect. However, satellite data often misses street-level conditions, and ground sensor networks rarely cover entire cities. High-resolution climate models such as UrbClim and WRF at 100-metre resolution, combined with machine learning methods predicting the Universal Thermal Climate Index (UTCI) at pedestrian scale, offer information more directly relevant to health outcomes than surface temperature alone — a point supported by NASA Earthdata satellite training resources and AI-driven systematic reviews of urban heat forecasting.
Several cities are already moving in this direction. Heat Action Plans — the most important planning instruments are in use in Delhi and Varanasi, while digital twins in Coimbatore and Bhopal allow scenario testing before implementation, embedding AI, satellite data, and 2050 projections into ward-level, building-level vulnerability planning. Mumbai’s Municipal Corporation tracks solar-reflective paint performance on schools in real time via IoT sensors. Pairing predictive modelling with real-time GIS-based early warning systems, as proposed in the Urban Heat Management Strategy for Asia-Pacific, represents the most comprehensive regional framework currently available. Other approaches include aligning smart city platforms with the UN United for Smart Sustainable Cities (U4SSC) framework and city-wide hotspot mapping in Dhaka. Where formal sensor networks are sparse, vehicle-mounted sensors operated by volunteers generate hyperlocal surface temperature data that neither satellites nor fixed networks capture. A colour-coded heat alert system sending zone-specific advisories to residents, paired with public water supply points during extreme heat events is another good technology.
On what works at scale, an award-winning programme in Indonesia applies high solar-reflective paint (SRI 106; solar reflectance 0.84), recording indoor temperature reductions of 1 to 3°C in residential buildings and up to 10.7°C in industrial ones, with roof surfaces falling by as much as 13°C. Evidence across Melbourne, Guangzhou, and Osaka confirms high-albedo coatings consistently deliver 1 to 2°C surface temperature reductions. Regulatory mandates — as seen in Osaka and New York City’s Local Laws 92/94 — demonstrate that when cool or green roofs are required rather than optional, thermal performance improves across entire building stocks. Cool roof work in Delhi’s informal settlements and NRDC policy factsheet document how this applies in lower-income contexts. Urban forests, green roofs, and blue infrastructure can reduce local temperatures by 2 to 5°C and could be integrated into India’s PMAY-Urban affordable housing programme for cooling to reach the urban poor by design. Miyawaki forests, as implemented in Kochi, deliver significant canopy cover on small plots through high-density planting. Earthenware-based passive cooling solutions from rural and border areas of Indonesia offer a low-cost, culturally grounded approach without reliance on formal supply chains. Cooling corridors combining reflective materials, water features, and clay pot coolers have produced measurable heat island reductions across Southeast Asian cities. Pairing green roofs with vertical bifacial solar PV panels, with panel output used directly for space cooling, offers another commercially viable model. Shaded public walkways and accessible water points and mandatory rest periods during peak heat hours for outdoor workers address the populations with greatest direct heat exposure.
The critical question is why so few approaches have scaled beyond pilots. The gap is not primarily technical. Heat falls hardest on low-income households, outdoor workers, and older people — those least able to fund, maintain, or navigate complex green infrastructure programmes. Fragmented data, absent maintenance financing compound this. Cities are losing green cover faster than they replace it, and nighttime cooling is becoming less reliable, meaning the problem worsens even in cities that believe they are responding.
Two technical caveats are almost entirely absent from mainstream policy guidance. First, in dense urban settings, cool roofs can redirect reflected solar radiation to adjacent buildings through the Sky View Factor effect, potentially intensifying localised heat stress, making urban morphology assessments essential before deployment. Second, green infrastructure over compacted or sealed ground underperforms significantly on evaporative cooling; restoring soil permeability and moisture capacity are prerequisites, not optional enhancements. The risk of green gentrification — environmental improvements that raise property values and displace the residents they were meant to protect — also demands explicit attention.
The underlying governance challenge is that too many cities still manage heat as an emergency rather than a long-term condition. What separates cities genuinely adapting from those that are not is whether data, design, policy, and finance have been brought into a single coordinated system, with heat mitigation embedded in zoning laws through minimum tree cover ratios, cool roof requirements, and ventilation corridor standards rather than left to voluntary adoption. Heat Resilience Toolkits spanning technology, building codes, financial incentives, and community engagement are now available to support this.
On financing, two instruments merit serious attention but rarely feature in regional discussions. Performance-based contracts pay private partners against verified cooling or energy outcomes rather than upfront capital, aligning incentives to results. Resilience bonds, unlike conventional green bonds, can be structured around heat-health outcomes, giving municipalities a durable funding stream. Blended finance and public-private partnerships are practical near-term enablers in resource-constrained settings. The equity dimension needs to be explicit. Financing mechanisms must account for the differentiated needs of women, men, and marginalised groups. District cooling systems offer an efficient alternative to thousands of individual air-conditioning units in high-density zones, and regulating private vehicle use should be treated as a thermal management strategy, not only an air quality measure.
The technologies, frameworks, and financing instruments to manage urban heat across Asia-Pacific already exist. The constraint is not invention but integration — bringing tools together to reach communities carrying the greatest heat burden. Scale requires regulatory mandates, not just incentives. Equity requires deliberate targeting, not the assumption that benefits will reach those who need them most.
Click any country to expand its case studies.
The Urban Heat Solutions Accelerator, led by WRI Brazil, is designed to help cities develop, finance, and implement solutions to reduce the impacts of extreme urban heat. It supports municipalities in designing integrated heat action plans that combine cool infrastructure, green cover, and community-level early-warning systems.
China initiated large-scale urban heat mitigation through the U.S.-China Clean Energy Research Center (CERC) Cool Roof Infrastructure project, with natural-exposure trials in multiple cities testing reflective cool roofs and black/white/garden roof configurations. The Guangdong Provincial Academy of Building Research (GPABR), Research Institute of Standards and Norms (RISN), Chongqing University, and the Chinese Academy of Sciences all contributed to the effort. Evidence from Guangzhou and other cities confirms high-albedo coatings consistently deliver 1–2°C surface temperature reductions.
To reduce extreme heat and energy demand, Amravati became the first Indian city to mandate cool roofs, integrating heat mitigation into urban planning with financial incentives and digital performance monitoring by the Amravati Municipal Corporation. Mumbai’s Municipal Corporation tracks solar-reflective paint performance on schools in real-time via IoT sensors. Heat Action Plans are active in Delhi and Varanasi, while digital twins in Coimbatore and Bhopal allow scenario testing with 2050 climate projections embedded at ward and building-level.
Indonesia launched a Urban Heat Island (UHI) Action Plan within the Climate Resilience Policy 2020–2045, featuring UHI mapping in 10 metropolitan areas including Jakarta, Medan, and Surabaya, early-warning systems via the CoCHAP project, and long-term financing for scaling best practices. An award-winning programme applies high solar-reflective paint (SRI 106; solar reflectance 0.84), recording indoor temperature reductions of 1–3°C in residential buildings and up to 10.7°C in industrial ones, with roof surfaces falling by as much as 13°C.
Japan uses innovative cooling materials and wearables — including heat-releasing clothing and UV-blocking parasols developed by Toray and Ogawa Co. Ltd — to reduce heat stress and improve thermal comfort efficiently. Evidence from Osaka confirms mandatory cool and green roof requirements deliver measurable thermal performance improvements across entire building stocks when regulatory rather than voluntary.
Malaysia is deploying green roof technology as a primary urban heat mitigation strategy, installing vegetation layers on building rooftops to increase moisture and reduce surrounding air and surface temperatures. The technology also provides thermal insulation that lowers building cooling energy demand. Green walls and sky gardens are being integrated into high-density mixed-use developments in Kuala Lumpur as part of urban resilience planning.
South Korea deploys a combination of fog cooling, cool roofs, shading structures, water features, and IoT sensor networks to reduce heat and enhance climate-resilient urban environments, coordinated through the Korean Ministry of Environment. Real-time thermal sensor data guides targeted cooling interventions in high-risk urban hotspots, demonstrating how integrated smart-city platforms can actively manage heat emergencies.
Since the 1970s, Basel has implemented mandatory and incentivized green roof policies supported by public financing through environmental and energy funds, covering the Department of Environment and Energy and Department of Building and Transport. Over time the city incorporated thermal mapping and climate modelling tools to identify urban heat islands and guide targeted interventions, making Basel a global reference for policy-driven urban greening at scale.
Taiwan is advancing the Strategy on Mitigation of Urban Heat Island (SOMHI), a national project by the Architecture and Building Research Institute, Ministry of Interior, aimed at popularizing urban heat island improvement measures and embedding long-term mitigation strategies across Taiwanese cities. The programme includes building material standards, albedo requirements, and urban planning guidelines.
Bangkok uses heat mapping, climate modelling, and early-warning systems to identify hotspots, reduce heat risks, and support climate-resilient urban planning, backed by a partnership between the World Bank and Bangkok Metropolitan Administration. The programme identifies the most heat-exposed districts, prioritizes cooling interventions such as urban forests and cool pavements, and integrates heat alerts into public communication systems.
San José’s Green Stormwater Infrastructure (GSI) Plan uses natural systems to manage stormwater, simultaneously reducing urban flooding, improving water quality, and mitigating urban heat through permeable surfaces, bioswales, and tree canopy expansion across the city. San José demonstrates how integrated green infrastructure policy can address multiple urban climate risks within a single programme framework.
AI and Geospatial Technologies for Climate Change Mitigation
Vaiyapuri & Golden Julie. AI analyses satellite data to detect heat islands, enabling resilient planning, guiding green infrastructure, and supporting data-driven climate policies and emissions reduction.
Artificial Intelligence Applications in Urban Extreme Heat Management: A Systematic Review
Jin Rui, Zahratu Shabrina, Wenjing Gong. Reviews AI across four dimensions of urban heat governance: prediction/early-warning, monitoring/assessment, mitigation/adaptation, and scenario simulation/decision-support.
Climate Change Made the Deadly Heatwaves Across Asia More Frequent and Extreme
Zacharias, Clarke et al. Urban heat is a growing health and economic risk worsened by climate change. Effective response combines immediate measures (alerts, cooling) with long-term planning (green infrastructure, resilient design) targeting vulnerable populations.
Combating Urban Heat: Systematic Review of Urban Resilience and Adaptation Strategies
Fu, Zheng, Sarker, Lv. Identifies urban greening strategies, heatwave early-warning systems, and community involvement projects as specific measures to enhance urban resilience and mitigate vulnerability to urban heat.
Decoding the Urban Heat Stress Among Indian Cities
Somvanshi & Kaur (CSE India). Provides a detailed analysis of how heat in Delhi is evolving, showing the city’s crisis is driven by a complex interaction of temperature, humidity, land surface conditions, and urbanization.
Global Projections of Heat Exposure of Older Adults
Falchetta, De Cian, Wing, Carr. Projects doubled heat exposure by 2050, with 23% of older adults at risk — especially in Asia and Africa — urging urgent policy action to protect the most vulnerable urban residents.
Linking Digital Twin Paradigm for Urban Heat Monitoring and Policy Integration
Hossain, Hosan, Ferdous. Introduces Digital Twin as a transformative approach integrating real-time sensor data, geospatial information, and meteorological forecasts to comprehensively monitor and reduce urban heat.
Mitigating Urban Heat Islands in the Global South: Data-Driven Approach
Chakrabortty, Pramanik, Zhran. Uses an urban cooling model to quantify heat mitigation via albedo, evapotranspiration, and green cover; recommends policies like reflective surfaces, incentives, and advanced cooling investments.
Prioritizing Nature-Based Solutions and Technological Innovations to Accelerate Urban Heat Mitigation
Zhao, Carmeliet, Hamdi et al. Proposes strategies integrating nature-based solutions (urban greenery) with emerging technological innovations to mitigate urban warming and accelerate capacity building efforts.
Unlivable: What the Urban Heat Island Effect Means for East Asia’s Cities | World Bank
World Bank report examining how urban heat islands interact with climate change to intensify heat risks for East Asian cities, with rapid urbanization, dense infrastructure, and reduced green cover trapping heat.
Urban Heat & Equity: Experiences from C40’s Cool Cities Network
C40 Cities (2021). Urban heat affects communities unevenly; C40 cities apply environmental justice principles to reduce inequities and protect vulnerable populations from extreme heat risks through targeted cooling programmes.
Urban Heat Island Adaptation and Mitigation in Practice: Lessons from Five Cities
Lau, Yuan, Ng. Integrates scientific insights into planning and regulations; uses GIS and advanced modelling for urban heat analysis; promotes scalable solutions like urban greening, high-albedo materials, and ventilation-focused design standards.
American Planning Association | Urban Heat Knowledgebase
Comprehensive planning resource covering heat island causes, measurement, policy frameworks, and design tools for urban heat resilience across jurisdictions.
California Heat Island Mitigation Program
State-level programme providing guidance, incentives, and tracking for cool roofs, cool pavements, and urban greening across California’s diverse urban contexts.
CSE India | Urban Heat Stress Tracker (Delhi)
Centre for Science and Environment’s real-time tracker monitoring Delhi’s urban heat stress using satellite and ground data to guide policy and community-level responses.
Google Heat Resilience Tool for Cities
Google’s AI-powered heat resilience analytics platform helping cities identify the highest-risk urban heat zones and evaluate the cooling impact of various green and cool infrastructure investments.
Heat Island Group | Lawrence Berkeley National Laboratory
Global research centre on cool roofs, cool pavements, urban forestry, and heat island science; provides tools, datasets, and policy recommendations for urban heat mitigation worldwide.
NASA ARSET | Applied Remote Sensing Training
NASA’s training programme on satellite-based tools for urban heat monitoring, including use of Landsat, ECOSTRESS, and Sentinel-3 for Land Surface Temperature analysis in city planning.
Urban heat is not only an environmental challenge but also a human dignity, health, and justice issue, particularly affecting vulnerable populations in rapidly urbanizing regions across Asia-Pacific.
Drawing from human values, global best practices, and emerging technologies, I would like to share a holistic response:
1. Ethical Foundation
The teachings of all religions encourage environmental care, tree planting, water conservation, and protection of all living beings. Therefore, mitigating urban heat is a moral responsibility, ensuring protection for current and future generations.
2. Nature-Based & Low-Cost Solutions (High Impact)
Proven global and OIC-relevant practices include:
- Urban afforestation & green corridors (tree canopy expansion reduces surface temperature significantly)
- Blue infrastructure (ponds, lakes, rainwater harvesting)
- Cool roofs & reflective materials (low-cost solution for dense cities like Dhaka)
- Green roofs & vertical gardens in urban buildings
Countries can scale these through community-based endowment models and public-private partnerships.
3. Smart Technologies (AI, IoT, ICT Integration)
Emerging technologies can significantly enhance urban heat response:
- IoT-based heat monitoring systems: Real-time temperature, humidity, and air quality sensors
- AI-driven urban heat mapping & prediction: Identifies heat hotspots for targeted intervention
- Satellite data & GIS platforms: Supports planning and early-warning systems
- Smart citizen apps: Alerts for heatwaves, hydration reminders, and safe zones
These solutions align with Smart Sustainable Cities initiatives like United for Smart Sustainable Cities (U4SSC).
4. Policy & Urban Planning Innovations
- Integrate heat-resilient urban design in city master plans
- Promote intergenerational procurement (long-term climate resilience)
- Enforce building codes for ventilation, insulation, and green coverage
- Establish cooling centres for vulnerable populations
5. Social Justice, Peace & Inclusion
Urban heat disproportionately impacts low-income communities, elderly, children, and outdoor workers. Responses must ensure equitable access to cooling solutions, community awareness and behavioural change, and gender-sensitive and inclusive climate policies. Climate resilience contributes directly to peace, stability, and human security.
6. Bangladesh & Asia-Pacific Context
In countries like Bangladesh, dense urbanization and limited green space increase vulnerability. Practical actions include scaling cool roof programs, expanding urban green belts, deploying low-cost IoT sensors in pilot smart city zones, and integrating climate tech into national ICT and SDG strategies.
Conclusion: Addressing urban heat requires a holistic, ethical, and technology-enabled approach combining faith-based responsibility, nature-based solutions, smart technologies (AI, IoT, ICT), and inclusive governance. Protecting the Earth is protecting humanity — let us act collectively to ensure a sustainable, peaceful, and resilient future for all people.
The Urban Heat Management Strategy in Asia-Pacific outlines a comprehensive, versatile approach and interconnected strategies for reducing urban heat island effects around a city space and its surroundings. For effective working and planning for mitigating urban heat island stress in the Asia-Pacific region, two fields need to be combined: firstly, materialistic deployment like cool roofs, green spaces, and climate-resilient infrastructure/construction materials, and secondly the applications based on predictive ML/AI Learning. These tools can be used for futuristic monitoring, early-warning and heat mapping as per GIS systems. Urban heat management strategies combine sustainable design (green infrastructure, reflective materials, shading) with advanced meteorological monitoring (remote sensing, GIS, and AI forecasting). The nearest coordinates for a central cityscape are used for monitoring the heat and temperature caused by intense sunlight. These are observed through satellite imagery and real-time sensors. The obtained information from the data (for UHI) is used in developing policy integration and sustainable urban planning.
The key enablers linking all elements can promote heat resilience infrastructure for densely populated regions: AI & Urban Intelligence (including predictive mapping, monitoring, and early-warning systems), Nature-Based Solutions (such as natural cooling, green spaces, trees, green roofs, and walls), Resilient Infrastructure (featuring cool roofs and pavements, cooling centres and shelters, energy resilient systems), and Community Engagement (focused on equitable access). These key enablers ensure that planning, mapping and analysing relationships between entities in a network and a circular flow can promote heat resilience in densely populated Asia-Pacific regions.
Yes, there is very much heat here.
Urban heat management has shifted from emergency response to long-term resilience planning, and we must take prompt action.
Dear COP Moderating Team,
Thank you for your kind invitation and for highlighting this important query on urban heat in the Asia-Pacific region. I am pleased to contribute my perspectives based on ongoing work and experience in Bangladesh and related global initiatives.
Urban heat is indeed a critical challenge for rapidly urbanizing regions. Addressing it effectively requires an integrated approach combining advanced technologies, nature-based solutions, and policy frameworks.
1. Technology-driven solutions
Cities should adopt geospatial technologies, remote sensing, and AI-based analytics to monitor urban heat islands in real-time. IoT-based environmental sensors can support localized temperature and air quality monitoring. Digital twin technologies and smart city platforms can further help simulate and optimize urban planning decisions.
2. Scalable green and cool solutions
Nature-based solutions such as urban forests, green roofs, vertical gardens, and water-sensitive urban design are highly effective. In addition, cool roofs, reflective pavements, and heat-resilient construction materials should be promoted through incentives and regulatory standards. Public-private partnerships can accelerate scaling in dense urban environments.
3. Planning, policy and financing frameworks
Urban heat mitigation must be embedded in national and city-level development plans. This includes integrating climate-responsive urban planning, strengthening building codes, and adopting data-driven decision-making tools. Financing mechanisms such as green bonds, climate funds, and blended finance models can support implementation, especially in resource-constrained settings.
From Bangladesh’s perspective, integrating ICT-based solutions with sustainable urban planning and community engagement can significantly enhance resilience to urban heat challenges. I look forward to further knowledge exchange and collaboration within this Community of Practice.
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A relatively new technical solution is green roofs with vertical solar PV (bifacial panels). The solar output can be utilized directly for space cooling in the host building. The business model can be the same as traditional rooftop solar options.
Also, as others have noted, urban forests or urban greenery is a great solution. A logical complement is to use permeable pavement for stormwater control or flood prevention. The business model is flood prevention insurance. The insurance and re-insurance industry is supposedly interested in climate adaptation, so these companies should be willing to support delivery of these solutions. These technical solutions are available and may be used.
Urban heat isn’t just a climate issue — it is a planning, governance, and equity problem. The cities making real progress are the ones blending data + design + policy + finance into one coordinated system rather than treating heat as a standalone concern.
1. Tech Solutions Cities Are Using Today
a) Geospatial & satellite intelligence: Cities are using platforms like Google Earth Engine and NASA thermal datasets to map urban heat islands (UHI) at neighbourhood-level. This allows identification of “hotspots” (often low-income, low-tree-cover areas) and prioritization of interventions.
b) IoT-based hyperlocal sensing: Low-cost temperature and humidity sensors mounted on streetlights or buildings give real-time microclimate data. These are especially useful in dense cities where satellite data alone misses street-level variation.
2. Scaling Green and Cool Solutions in Dense Cities
a) Urban forests (strategic, not cosmetic): Focus on heat-vulnerable zones, not just beautification corridors. Use native, drought-resistant species to reduce water stress.
b) Cool roofs & reflective materials: One of the fastest, lowest-cost solutions — especially for informal settlements. Programs like Ahmedabad’s cool roof initiative show measurable temperature drops indoors.
3. Planning Frameworks, Policies & Financing Mechanisms
a) heat-resilient urban planning frameworks: Embed heat mitigation into master plans, zoning laws, and building codes. Mandate minimum tree cover ratios, cool/green roof requirements, and ventilation corridors (wind pathways).
b) Digital planning tools: GIS-based planning platforms + urban digital twins for scenario testing. Integration of land use, transport, and climate data into one decision system.
I wish to share details of our project in Indonesia — we have a cool roof and cool house project.
Integrated solutions combine technology, early-warning systems (EWS), planning, and financing. Leveraging tools may be used such as geospatial data for mapping, IoT & AI enabled cooling with EWS. Scale up practical measures — green roofs, reflective paint, improved ventilation, urban greening, and cooling shelters (including repurposed public spaces) — supported by inclusive heat action planning, as well as policies and financing mechanisms that are responsive to the differentiated needs of women, men, and marginalized groups.
I live in one of the hottest and most polluted cities in the world, Delhi, India. Indian cities are increasingly deploying a multi-layered technology stack combining satellite data, IoT, and AI to diagnose urban heat with precision. Satellite-based thermal remote sensing integrated with GIS enables the creation of detailed urban heat maps that identify hotspots and guide targeted mitigation.
Key tech solutions being deployed in Indian cities:
- AI & Vulnerability Mapping: Delhi’s 2025 Heat Action Plan (HAP) embeds AI and satellite data to create building-level vulnerability maps; collaborations with IIT Mandi and Resilience AI identify the hottest micro-clusters.
- Digital Twins: Pilot projects in Coimbatore and Bhopal (2024–25) integrate geospatial thermal data and urban morphology to simulate heat dynamics and test mitigation scenarios before physical implementation.
- Geospatial Heat Mapping: Cities like Ahmedabad and Nagpur use GIS platforms to embed thermal intelligence into master plans and HAPs.
- Reflective/Cool Roof Monitoring: Mumbai’s BMC has coated municipal buildings and schools with solar-reflective paint, with IoT-supported performance tracking.
- Ward-Level Predictive Planning: Varanasi’s ward-level HAPs align with climate forecasts up to 2050 to guide investments in cool roofs and green spaces.
Nature-based solutions (NbS) like urban forests, green roofs, and blue infrastructure can lower local temperatures by 2–5°C. Green PMAY Integration: Incorporating reflective materials and green building codes into affordable housing under PMAY-Urban can embed cooling solutions at scale for the urban poor.
Policy & Planning Tools: Heat Action Plans (HAPs) — Ahmedabad’s 2013 HAP is a global pioneer; newer-generation HAPs in Delhi and Varanasi embed AI, satellite data, and 2050 projections. ICLEI’s Heat Resilience Toolkit for Indian cities identifies causes and prioritizes solutions across four categories: technology/infrastructure, policy mandates (building codes), incentives/financing (rebates, grants), and community participation. Embedding thermal vulnerability maps and green coverage norms into city master plans is now a recognized best practice. However, implementation is mostly in tier-one cities only, hence more policy initiatives need to be put in place to improve the overall situation across the country.
1. Effective Technology Solutions for Understanding and Reducing Urban Heat
The most robust approaches combine remote sensing, high-resolution urban climate modelling, and GIS-based spatial analysis. Satellite-derived Land Surface Temperature (LST) data, from platforms such as Landsat, ECOSTRESS, and Sentinel-3, offer city-scale mapping of heat patterns, while dense networks of fixed and mobile in-situ sensors provide the localized, real-time ground truth needed to validate those models. Neither approach alone is sufficient: remote sensing captures broad spatial variability but misses fine-grained microclimate dynamics, while sensor networks are often too sparse to cover entire cities.
For rapidly growing Asian cities, a practical middle ground lies in integrating these data streams through GIS-based multi-layer analysis. This allows planners to overlay thermal exposure maps with urban morphology data (building density, sky view factor, street canyon geometry) and population distribution, making it possible to identify where heat stress is most intense and who is most exposed simultaneously. High-resolution urban climate models such as UrbClim or WRF, operating at 100-metre resolution, are increasingly being used in this role across European cities and could be adapted for similar applications in the Asia-Pacific context. Machine learning methods have also shown promise for downscaling coarse satellite data and predicting thermal comfort indices such as UTCI (Universal Thermal Climate Index) at pedestrian scale, which is more directly relevant to health outcomes than surface temperature alone.
2. Scaling Green and Cool Material Solutions in Dense, Fast-Growing Areas
Building-level interventions (green roofs, cool roofs, green façades, reflective pavements), neighbourhood-level greening (street trees, green corridors, urban wetlands), and district-scale design choices (building layout, ventilation corridors, urban form) all play a role. A consistent finding is that no single measure is sufficient. In dense areas with limited land, building-scale passive solutions tend to have higher implementation feasibility. Cool roofs with high-albedo coatings have demonstrated measurable surface temperature reductions of 1–2°C in demonstration areas across cities as different as Melbourne, Guangzhou, and Osaka. Green roofs and façades provide additional co-benefits including stormwater retention and biodiversity, which are particularly relevant in tropical and subtropical climates.
The more difficult challenge is maintenance and long-term performance. Green infrastructure requires sustained operational investment that resource-constrained cities often cannot guarantee. One approach that has shown traction in East Asia is regulatory mandates combined with municipal subsidy programmes: Osaka’s green building ordinance and NYC’s Local Laws 92/94 both demonstrate that mandating green or cool roofs at scale can shift baseline surface thermal properties city-wide, though enforcement capacity varies considerably between high-income and lower-income contexts. For fast-growing cities in South and Southeast Asia where informal settlement patterns make top-down mandates harder to apply, community-level implementation, pairing awareness campaigns with accessible cool material retrofits, may offer a more realistic near-term pathway.
Urban heat is emerging as a silent intense killer. I am sharing some of my thoughts on urban heat discussion below:
- We need a better network of sensors to measure heat and its impact. Currently the heatwave alerts are based on limited sensors in cities which ignore the differential vulnerability aspect of heat. One of the localized ideas could be to call for volunteers to install sensors on their vehicles to measure surface temperature which can be used to identify heat patterns. This will also pave a path to better geospatial intelligence and increase citizen participation.
- One of the major challenges in the cities is the lack of space. We need to move to an integrated green infrastructure which takes development and improving the microclimate of the cities together. Some of the methods include Miyawaki forests (implemented in Kochi), implementation of cool roofs by using reflective paints and cool construction materials, and avoiding usage of glass as a construction material to reduce building energy.
- We need to be able to move from pilot projects to scaling systemic policy. We can do so by first identifying vulnerable populations and areas that are affected the most by heat. Because this is a function of many indicators like socio-economic status and housing, this adds to a multiple-layered problem which needs better measurement to solve the larger issue of urban heat. Citizen science is an effective tool to solve this data crunch in places where resources are limited. In addition, we also need to make people aware of this issue and amplify the need for long-term solutions.
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Thought-provoking discussion. Planting dense native trees along roads, schools, bus stops, and slum clusters can reduce surrounding temperatures significantly.
Issues in the Asia-Pacific are not limited to climate change; there are issues associated with urban density, informal settlements, poor infrastructure, and energy poverty. Thus, any heat relief solutions developed for such places need to take into consideration cost and community participation rather than purely being technologically driven.
Mud building materials have been known to keep houses cool. The heat in Asia-Pacific could be mitigated by using mud for building houses. These houses could be covered with green roofs which would not only serve to bring oxygen into the environment but also keep the houses cool as well.
Secondly, more trees could be planted to purify the air. Plants such as snake plants oxygenate the air, thereby reducing the heat. Burning of industrial waste could also be reduced. Cleaner options such as solar and wind power could be introduced to substitute fossil fuel. Digitalized electric cars are environmentally friendly and will not add to environmental heat.
Furthermore, digitalized geoengineering measures such as cloud seeding could be carefully and sparingly used to create rain in this region, which will serve in dousing the heat with rainwater and cooling the environment. However, this should be measured and carefully used to avoid a counter effect such as dangerous floods.
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Dear Members,
I would like to share a few inputs on the topic of urban heat, specifically drawing from what I have observed and thought about in the context of Delhi. The following are solutions I feel could be worth exploring or strengthening:
- Use of heat-reflective paint on rooftops: Applying heat-reflective paint tested on roofs can help block UV rays and keep buildings and apartments cooler. This is a low-cost and accessible option. Public water supply points: The government could introduce water supply points at regular intervals (such as every 1 km) to ensure people have access to water when moving through the city during heat.
- Shaded walkways: Providing sheds or covered walkways along public routes so people can move through the city without direct sun exposure.
- Color-coded heat alert system: A system that uses a heat map of Delhi to identify the most heated and humid zones and sends alerts to people accordingly. For example: “This is a high heat area — please do not go out without an umbrella or water” or “This is a safer zone — you can stay here.”
These are ideas gathered from observing what is happening in Delhi and thinking about what technology, particularly AI and remote sensing, might help make more effective. Below are some related resources addressing these 4 viewpoints in detail:
- Amid scorching temperatures, India turns to ideas both old and new to beat the heat — UNEP ↗
- Cool Roofing Solutions for Reducing Heat Stress in Delhi Slums — EPIC-India ↗
- Cool Roofs Policy Factsheet (NRDC, December 2023) ↗
- Singapore: Tackling urban heat island effect with innovation — PreventionWeb ↗
- Cool Walkability Planning — Planetizen Blogs ↗
- Bangkok Post — Urban heat is a man-made hazard ↗
- Heatwave Map Spotlight: Northern, Central, and Eastern India — IQAir India ↗
- Satellite Remote Sensing for Measuring Urban Heat Islands and Constructing Heat Vulnerability Indices — NASA Earthdata ↗
- Australia: Smart Satellite Mapping to Combat Urban Heat Risks — OpenGov Asia ↗
- Artificial intelligence applications in urban extreme heat management: A systematic review — ScienceDirect ↗
Dear Members
Thank you for excellent and enriching discussions on Urban Heat so far. I would like to add a few points not raised so far.
1. Technical Assumptions
a. Cool roofs: Cool roofs are supposed to be critical in urban heat mitigation. However, in some contexts, they may produce adverse outcomes. For example, in dense urban environments with narrow streets, reflected solar radiation doesn’t always escape into the upper atmosphere but is redirected to adjacent buildings, intensifying heat stress (called by researchers the Sky View Factor). We need to keep this in mind else we will replace one thermal problem for another.
b. Soil health: Soil health presents another blind spot. Nature-based solutions are often shown as scalable interventions, but only where the substrate supports them. Green infrastructure installed over compacted or sealed ground will always underperform. De-paving and restoring soil moisture capacity determines whether nature-based solutions deliver evaporative cooling in practice or merely in theory.
2. Financing Superstructure
Getting initial capital for cooling infrastructure is challenging but achievable. However, sustaining such infrastructure over decades is where most strategies fail. Two instruments deserve serious examination here:
a. Performance-based contracts where private partners receive remuneration tied to verified cooling or energy outcomes rather than upfront expenditure.
b. Resilience bonds: unlike conventional green bonds, these can be structured specifically around heat-health outcomes, providing municipalities with a more durable and accountable funding stream than time-limited grants.
3. Social Equity Issues
a. Mandatory Rest Periods for outdoor workers: Heat is not a neutral phenomenon. It affects disproportionately those with the least capacity to adapt, and any strategy needs to resolve social equity issues. Outdoor workers bear the highest levels of direct heat exposure and need protection — perhaps in the form of mandatory rest periods during peak temperature hours and adjusted working schedules.
b. Ensuring that greener buildings do not displace lower-income people: As environmental quality of residences improves, property values tend to go up, and lower-income residents are displaced. Adequate measures to protect against such displacement could be integrated into design.
4. Integration into City Planning
Reducing private vehicle use in cities needs to be recognised as a thermal management strategy, not merely as a pollution-reducing issue. Similarly, for high-density urban zones, district cooling systems could be considered seriously as they are centrally managed and thermally efficient, addressing the cumulative heat load generated by thousands of individual air conditioning units operating simultaneously across a city.
Hope this helps enrich the discussion.
Dear members, good afternoon.
While researching urban heat islands today, I generated this infographic (using AI) that I think is quite insightful. I feel it offers a helpful way to revisit the basic understanding of the phenomenon, while also presenting both the challenges and potential solutions in a clear and visually engaging manner. Thank you. Click here to view ↗
Many thanks to all who contributed to this query!
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