Sometimes called an invisible disaster, extreme heat is increasingly affecting how people live in Indian cities.
About 57% of Indian districts, home to over three-quarters of the population, are now considered at high to very high risk. Urban populations are particularly exposed due to the urban heat island effect which makes cities hotter than the nearby countryside.
Cities are often warmer than the countryside that surrounds them due to several factors: there are typically fewer trees to provide shade and cooling; a greater number of concrete and brick buildings which can absorb heat; and more energy use which produces waste heat. The result is known as the urban heat island effect.
For many households, living conditions exacerbate heat. Asbestos roofs, poor ventilation and overcrowding increase indoor temperatures. While outside, there may by a lack of access to shade or open spaces. Health consequences and deaths are rising as climate change drives temperatures up.
But talk of emissions reduction often does little to motivate change. We need to talk about adaptation with a different emphasis. For policymakers, the goal may be saving lives or reducing emissions. But for someone buying an air conditioner (AC), the priority is usually comfort and cost.
This article came out of a Dialogue Earth panel on urban heat at Mumbai Climate Week, “Is India getting too hot for roti, kapda aur makaan?” Thanks to everyone who took part.
Fixing the buildings
The urban residents who are contributing most to heat islands are those who have access to ACs, refrigerators and other household devices. Often, they are not cooling themselves in efficient ways.
Today, the dominant solution is individual ACs. Costs and emissions can be cut through systems that serve entire buildings or clusters, such as heating, ventilation and air conditioning (HVAC) and district cooling systems. But these are capital-intensive, requiring upfront investment at the construction stage. In India as elsewhere, developers want to sell fast and exit.
In commercial buildings, energy efficiency has gained traction because high-value corporate tenants now demand it. But in residential buildings, buyers tend to focus on price and location, and energy efficiency is rarely on the checklist. Developers have little incentive to absorb higher upfront costs.
This is a CATCH story
This story is part of Dialogue Earth’s work on the Community Adaptations to City Heat (CATCH) project, in partnership with Boston University. The project is funded by Wellcome. All Dialogue Earth content is editorially independent.
Read more stories from CATCH.
When consumers understand long-term savings, they begin to demand efficiency. That can push developers toward better cooling solutions.
India’s ongoing greenfield development offers a window of opportunity. The country is expected to add millions of square footage of built-up area in the next few years, with developers such as Prestige, Hiranandani and Puravankara working on projects ranging from semi-affordable for the middle class to ultra luxury.
Seeking solutions
Though it’s not perfect, retrofitting for efficiency can also provide benefits. Significant improvements can be made by using appliances with higher ratings for energy efficiency, integrating renewables like rooftop solar, and replacing conventional fans with brushless versions which reduce waste heat.
In some cities, if energy-efficiency measures are implemented in residential developments and quantified, housing societies can receive property tax rebates and residents in turn get reduced electricity bills. Even simple steps, like motion-sensor lighting in parking areas and communal toilets, can generate noticeable savings.
In Hyderabad and Chennai, some residential projects have installed central chiller systems. Back in 2015, developers of a Hyderabad residential society piloted a community cooling plant, avoiding the need for individual AC units on exterior walls. Flat owners were initially hesitant, but agreed to adopt the system, and cooling bills have remained stable for nearly a decade.
This was a collective win-win. Real savings drive adoption.
A dedicated department for energy-efficient cooling within the Bureau of Energy Efficiency could further accelerate change.
Not forgetting the most vulnerable
For vulnerable communities facing extreme heat, there remain very limited solutions. Their contribution to emissions is only a fraction of the total, yet they are often the ones who suffer the most from surging temperatures.
Most people in low-income settlements must rent. Because they don’t own their homes, they have no ability to change them, which means no ability to alter windows or doors and install ventilation systems to improve thermal comfort.
They also face cramped living conditions. In the greater Mumbai city of Mira Bhayandar, up to eight people often live in 150 to 200 square feet spaces – equivalent to a small studio apartment – with low ceilings. Fans may not provide enough relief in such circumstances, and many people end up going to gardens or sitting under trees to rest as indoor conditions become unbearable.
Parts of Tamil Nadu and Kerala have piloted the use of passive cooling measures such as coir roofing systems and cooling paint, with good results. But in large cities such as Mumbai, slums are densely populated, with houses built informally, meaning most retrofitting is a challenge. Homes in some slum areas have structurally weak roofs, for instance, making it difficult to implement any measures beyond lightweight additions.
Most low-income families also prioritise rent, food, education and healthcare. Heat-resilient housing upgrades naturally fall very low on their list because upfront costs are unaffordable, even if the benefits are clear.
Financing cannot be the responsibility of these households alone. The primary responsibility should lie with government and city authorities, supported by climate funds, development agencies and private sector partners. Implementation can happen through housing societies and community groups like bachat gats (microfinance self-help groups).
Importantly, vulnerable households do have agency. They are already adapting in small ways and are willing to invest when presented with affordable and trusted solutions.
For instance, in Mira Bhayandar, we saw that some people had put thermocol sheets – low-cost polystyrene panels – under their roofs to keep the heat out. And where interventions such as wood wool panel ceilings were installed, some households improved heat resilience further by adding LED lights, which emit less heat than older bulb types.
Clearly, communities are aware of heat-related issues and receptive to solutions, particularly when they are pragmatic and yield measurable benefits such as lower indoor temperatures and electricity bills. The use of these kinds of solutions can grow if more people know about them, can access them and can afford them.
And when communities can pool resources, access government incentives and clearly see the return on investment, upgrades become possible. What is needed is a financing system that is simple, accessible and designed around their realities. People respond to monetary benefits more than to technical jargon. Instead of emphasising carbon reductions in abstract terms, we must focus on practical outcomes: saving money and living better. That is what brings people on board.
