The world is heating up, and India is feeling the burn. According to the World Meteorological Organization, 2024 was the hottest recorded year, with global surface temperatures averaging 1.55°C above pre-industrial levels. The greenhouse gas (GHG) emissions that are causing this global heat crisis have still not reached their maximum. These extreme temperatures affected billions of people worldwide. In India, the authorities reported over 40,000 heatstroke cases across 17 states.

Some 360 million Indians are expected to face extreme heat-related stress by 2050. So, countries need to start insulating their citizens and economies against extreme heat. India, with support from the United Nations Environment Programme (UNEP)-led Cool Coalition, is starting to do just that.

Under the Heat Action Plan 2022, the Indian Meteorological Department and the National Disaster Management Authority (NDMA) directed 23 states to implement the plan and provided guidelines to enhance extreme heat resilience. Many sub-national governments have their own heat action plans.

Meanwhile, under the India Cooling Action Plan, India aims to reduce cooling demand by up to 25 per cent, refrigerant demand by 25–30 per cent and cooling energy requirements by up to 40 per cent by 2038. The plan also prioritizes other solutions, such as passive cooling, building design, fans and coolers, new technologies, and behavioural change.

These steps, many of which were recommended as global measures in UNEP's Global Cooling Watch report in 2024, are important not just to protect people and livelihoods, they are important to avoid a vicious cycle of increasing cooling demand burning through more power and further driving climate change. Such measures need to be formalized and included in climate pledges under the Paris Agreement,  known as Nationally Determined Contributions, which are due to be updated by February 2025 latest.

Combatting Urban Heat

City dwellers are severely impacted by the growing heat, suffering from the urban heat island effect (UHIE), whereby grey infrastructure and a lack of greenery traps heat and emits it a night, meaning that temperatures stay higher than in the countryside.

Most heat action plans in India lack a standardized scientific approach to mapping and assessing urban heat which is essential to enable more accurate risk assessment and support to effective heat mitigation strategies. The UNEP's projects are helping to fill this gap by supporting sub-national governments through UHIE assessments and passive cooling recommendations. A National Methodology for UHIE assessment has been developed by UNEP with CEPT University, which collects and overlaps data on land and surface temperature, land-use cover, building form, surface materials and nature of green cover. It's integration into the NDMA heatwave guidelines is in process.

In Tamil Nadu, UNEP and CEPT University have tested this methodology and identified hotspots across urban areas and provided recommendations for the 11 fastest-growing cities in the state including Chennai, Madurai and Thoothukudi. These mapping efforts, coupled with long-term technical assistance from UNEP, are helping Tamil Nadu's cities to take effective heat mitigation measures that can be scaled for the long-term through reconfigured urban master plans and construction norms.

Chennai has witnessed significant urban sprawl over decades, leading to increased temperatures—the result of less vegetation, higher built-up density, and a surge in anthropogenic heat emissions. Between 2013 and 2023, the mean night-time temperatures rose by 0.63°C. Over 64 per cent of the city now falls within high-temperature zones. Here UNEP, in partnership with CEPT University and the World Bank is using hotspot mapping and modelling to inform updates to the Chennai Master Plan.

Strategies for Cool Cities

Of course, there is more to beating the heat than assessments. UNEP and partners have identified a host of actions that will make a massive difference.

Building green infrastructure and restoring natural heat sinks, such as urban forests and water bodies, have been shown to reduce temperatures. Permeable surfaces, cool roofs and even simple fixes such as using light-coloured paints on walls reduce heat retention. Integrating climate-sensitive designs, optimized floor spaces and enhanced sky-view factors can make buildings cooler and more energy efficient.

Promoting shading, insulation, double-glazing and fans can massively enhance thermal comfort while bringing down emissions. Adopting
energy-efficient and optimized air-conditioning systems, and implementing district cooling systems, can keep both people and planet cool.

For example, in Tamil Nadu, UNEP is developing passive cooling guidelines that the Tamil Nadu government can integrate into local regulations and social housing procurement. UNEP is also working with the state government to better direct investments in nature and climate adaptation to respond to the heat crisis—a crisis that last year led the state to declare a heat disaster. UNEP is also engaging and supporting real estate developers and financiers of housing in the state to reorientate investments towards passive cooling—unlocking value from enhanced thermal comfort and reduced cooling loads.

Support to Get it Right

To implement the right strategies and measures, Indian state and city agencies require support to plan and implement long-term resilience measures. There are challenges that hinder progress, including limited access to reliable data and comprehensive UHIE analyses, no national framework to assess urban heat, insufficient capacity in cities for evidence-based policymaking and urban heat planning, a lack of dedicated financing for city-led interventions and often poor coordination across city departments.

Current heat action plans primarily emphasize short-term heat mitigation and emergency response; they must also integrate long-term urban planning strategies to incorporate sustainable, passive cooling solutions, and lower urban temperatures. A coordinated effort between disaster management authorities and urban planning departments is essential. Cities need expanded monitoring systems for temperature and humidity, along with technical and financial assistance for upgraded UHIE assessments following UNEP-CEPT's methodology. Urban planners should prioritize updates to master plans and local area plans in identified hotspots.

To get all this done, enhancing capacity among urban planners, developers, and disaster management authorities is essential. India needs dedicated heat officers, updated building by-laws to include passive cooling features, and financing programmes for greenfield and retrofit buildings and integrating long-term heat resilience into state and city heat plans.

 Initiatives like UNEP's India Cooling Programme, which prioritize extreme heat resilience through sustainable solutions, offer scalable models. Additionally, establishing national platforms and hubs can provide consistent support to cities.

 Extreme heat is a persistent challenge that requires coordinated global and local action. With scalable solutions, stronger policies and enhanced collaboration, Indian cities, which are on the frontline of the challenge, can show the world how it is done.  #