The Heat Trap | Why Indian Cities Are Finding It Harder to Stay Cool

[00:00:00]Every summer, millions of Indians ask the same question. Was it always this hot or has something changed?

[00:00:09]Summer has always been a part of life in India. But increasingly, scientists say another story is unfolding inside our cities.

[00:00:18]A story about disappearing shade, expanding concrete, and cities that are slowly losing the ability to cool themselves.

[00:00:36]It's 2:00 in the afternoon in New Delhi and the temperature is around 45° plus.

[00:00:43]It's not just about the temperature, but scientists and urban planners are now worried that our cities are increasingly trapping heat and amplifying it, which is directly having an impact on human health. Asphalt roads, concrete buildings, metal and steel construction, and of course the reduction of green cover are all taking their toll. Many people believe summers today feel different from the summers they remember growing up with. But is that simply perception or is something really changing?

[00:01:48]The feeling. that summers are changing is widespread and increasingly satellite data suggests people are not imagining it.

[00:01:56]>> It's it's not an imagination because you can see this. So earlier it used to be that we could have depended on imagination. Now we have satellite data.

[00:02:04]So when we compare the city from last 10 years and based on the variations which we have seen in the data. So data speaks itself and tells you that there is something which is going down right. So your green covers has gone down. Your water blue you can say blue and green infrastructure has gone down and your gray has gone up. The gray and black moment they add it will trap more heat.

[00:02:26]We can get to understand that which pocket of the city is heating up. But we may not have a reasons why this pocket is better than this one. Then you need a ground truth thing for that.

[00:02:37]>> The evidence is visible from above. A recent analysis by the Center for Science and Environment found that nearly 76% of Delhi's area is persistently heat stressed. The same analysis found that Delhi's green cover declined from around 25% in 2014 to about 14% in 2024.

[00:02:59]Water bodies have also shrunk. In simple terms, the city is losing some of its natural cooling systems.

[00:03:19]AC for older residents. The evidence is not found in satellite images. It comes from memory. Many remember more shade, more open spaces and nights that brought relief from the day's heat.

[00:03:48]The sun has already set, but the city is still holding on to the day's heat. One of the biggest concerns scientists point out today is not just hotter afternoons, but warmer nights. Roads, rooftops, buildings absorb heat throughout the day and slowly release it after sunset. And when cities fail to cool down, our bodies get less time to recover before the next hot day begins. Like in case of Delhi, it was a 12° variation. Now we see only closer to the 10 or 9.8. So that means over the over the 10 years, we understand that day and night temperatures are now shrunk. What will happen? Night helps you to de-stress.

[00:04:26]Like you you have done a lot of active work in the morning. You will have a cooler environment in the night time which will help your body to de-stress.

[00:04:33]But now you are in a in a situation where your body will take little more time to de-stress but that hours you don't have you have only 24 hours. So this is how the systems will get distress will build on to great extent.

[00:04:47]Researchers say Delhi's ability to cool itself at night has declined and that may be one of the most important changes taking place in urban India. The challenge is no longer simply surviving hotter afternoons. It is learning how to live with warmer nights. Heat is often measured in degrees, but people experience it through sleepless nights, exhaustion, dehydration, and reduced productivity.

[00:05:15]For outdoor workers, older people, children, and those with limited access to cooling, the risks can be far greater.

[00:05:25]For many families, the answer to heat is simple. Close the windows, switch on the air conditioner. But there is a paradox.

[00:05:33]As temperatures rise, more households are turning to air conditioners.

[00:05:38]According to estimates cited in the World Energy Outlook, air conditioner ownership in India has tripled over the last decade and it is expected to continue growing rapidly in the decades ahead. India's peak electricity demand has risen dramatically in recent years.

[00:05:55]Since 2019, peak demand has increased by around 90 gawatt. To put that into perspective, that increase alone is roughly equivalent to the entire peak electricity demand of France. Much of this increase is being driven by growing need for cooling during hotter summers and warmer nights.

[00:06:14]>> You have much more induced heat. So you you're uh you can say the heat which has been there trapped into the structure has been now flowing onto the uh streets. Now it'll go into your ambient.

[00:06:26]So it's a vicious cycle which is there.

[00:06:28]So more more air conditioning means more heat into the environment and after a particular stage will come where your air conditioner will come off. That's happening now.

[00:06:37]>> Every air conditioner cools the room inside. But the heat removed from that room is released outdoors. As more cooling is used, more heat is added to the urban environment. And as cities get hotter, demand for cooling rises again.

[00:06:53]But heat is not experienced equally.

[00:06:55]Some people spend much of the day in air conditioned homes, offices, and vehicles. Others cannot. Street vendors, construction workers, delivery riders, security guards, and many others. For them, heat is not simply discomfort. It is a part of the working day. The CSE study found that many construction sites, street markets, and informal settlements are located in areas experiencing recurring heat stress. In many cities, access to shade is becoming increasingly unequal. Some neighborhoods are protected by trees and open spaces.

[00:07:32]Others are exposed to long stretches of concrete and asphalt.

[00:07:38]Meteorological records provide the broader picture. Climate change is increasing the frequency and intensity of extreme heat. But the way cities are built often determines how people experience that heat. Heat may begin with the weather but increasingly it is becoming a city story. Now how you cut down the exposure that will decide whether your cities will survive or they will fail. Now exposure how you reduce it whether you want an emergency response or you want to improve what you have been doing wrong so far like so for example fragmented green or or the one which is like next to you will help you right so how you induce that or the water which is like there around you into your microclimate how you enhance your microclimate like right now what we are sitting at this stage though it's it's outside maybe 45 plus but right now we may be sitting at 35 36 because there are a lot of elements which has helped us to sit here in the sun and I'm not even sweating much right so this is microclimate now when you create this kind of microclimate and you learn from it and you try to expand into your cities definitely there will be hope so the people with good microclimate will survive so that means this is required you know there's nomenclature which exist and that's what impact is of the water and green to the microclimate if we induce that into our designs into our layouts into principles and looking for a good materials which can help us to do this.

[00:09:08]I think there is a possibility which we can turn this curve otherwise we have if the business as you goes slowly we are heading towards where we will not be having a livable city.

[00:09:18]The good news is that solutions already exist.

[00:09:22]Research shows that greener neighborhoods can remain significantly cooler than their surroundings. The challenge is not simply to build bigger cities. It is to build cooler and more resilient ones. And that may be one of the most important lessons for cities facing a warmer future. Cities have always changed, but the choices we make today about trees, roads, buildings, and public spaces, choices that will shape what summers feel like tomorrow. Heat may begin with the weather, but increasingly how we experience it depends on the cities we build, the trees we preserve, the shade we create, the water that we protect, and the choices we make about how we grow.

[00:10:08]Because the challenge facing our cities is no longer simply how to survive hotter summers. It is whether they can remain places where people can live, work, and thrive in a warming world. And perhaps the question is no longer whether our cities are getting hotter.

[00:10:25]The question is whether we are building them to stay cool. Because the choices we make today will shape how we live tomorrow.