Cold Comfort

ABOUT FOUR YEARS ago, when a group of engineers showed up at Jiralal Yadav’s tiny tin-roofed house in Pune’s Hadaspur area, with solutions to help cool it, Yadav was a little circumspect.

The engineers had a variety of solutions. There was a moveable aluminium foil sheet roof that provided a barrier against the sun and which could be controlled through a chain wheel-pulley mechanism, the idea of a lightweight rooftop garden, another which involved using discarded PET bottles filled with water and laid out in a lattice and affixed to the roof, one involving a dormer window which would provide a gateway for hot indoor air to escape outdoors and a few more. Yadav, a 45-year-old who worked in the construction sector and who had some experience of farming as a youth growing up in Uttar Pradesh, opted for a rooftop garden. “I thought even if it didn’t work, maybe I’d be able to grow something I could use,” he recalls.

The excessive heat in his house during summer was a real prob­lem. His family, comprising a wife and two kids, would spend their afternoons out of the house. Even at night, they would keep late hours, unable to fall asleep despite using fans, because the house remained hot and humid. They tried out simple solutions like covering their roof in a thick blanket to ward off the sun during heatwaves, but it provided little relief. “So, although I was doubtful that a garden would work, I wanted to try it out,” Yadav says.

The house, Yadav says, has cooled down considerably using this method. “It’s been around three or four years since we began using this method. And it takes a bit of time, watering and tending to the plants, which I enjoy, but the house is now much cooler,” he says.

The lightweight rooftop garden on Yadav’s house, along with the other solutions being deployed else­where, is part of a project being tried out by cBalance Solutions, a Mumbai-based social enterprise that works in the sustainability space. They have so far deployed these solutions in around 50 homes and five commu­nity buildings in low-income informal settlements across six Indian cities (Mumbai, Pune, Bengaluru, Delhi, Chennai and Coimbatore), and are now in discussions to scale it up.

“We wanted to address the glaring inequality that is present when it comes to addressing heat. The affluent are well-protected. They live in well-ventilated homes and use air conditioners. Yet, when there is too much energy consumption in summers and there are power cuts, it is the poor, who are already more vulnera­ble and are not the ones behind the jump in energy consumption, who suffer the most,” says Vivek Gilani, founder and managing director of cBalance Solutions.

Efforts such as Gilani’s are one of a few that are looking for ways to deal with the growing heat crisis in India. Another solu­tion being tried out in several cities is painting the roofs of homes with white solar reflective paint, although there have been some concerns raised about maintaining the whiteness of the roofs and the blindness it causes in birds flying over the roofs. Elsewhere in some cities, researchers are working with authorities to improve their emergency response plans.

Heat is increasingly becoming a major issue for the country. Studies show that its intensity, frequency and duration it lasts are rising. “Every year, the area under heat stress is increasing,” says Rajashree Kotharkar, an urban planner and professor of architec­ture and planning at Visvesvaraya National Institute of Technol­ogy in Nagpur who has been studying urban heat for several years. “Areas that previously did not have very high temperatures are also increasingly getting hotter. The whole country will, someday or the other, experience heat stress.”

This year—although we are only at the start of May—has been particularly warm. Temperatures have been soaring as high as 47 degrees Celsius in some parts of the country, with April seeing one of the longest spells of heatwaves extending in some regions to close to 15 days. In the first week of May, maximum temperatures in some areas of Telangana, Rayalaseema, Vidarbha, Karnataka and Madhya Pradesh soared as high as 44 to 45 degrees Celsius. In some parts of Marathwada, southeast Uttar Pradesh, northeast Madhya Pradesh, Chhattisgarh, north Odisha, Gangetic West Bengal, Jharkhand, Tamil Nadu, and coastal Andhra Pradesh, it ranged between 42 to 44 degrees Celsius, several degrees higher than normal. The India Meteorological Department has now issued a fresh heatwave warning for several regions across states.

All of this brings dangers. According to a paper published in The Lancet in 2022, the country saw a 55 per cent increase in heat-related deaths between 2000–04 and 2017–21. Last year in April, at least 14 people died of heatstroke and many more were hospitalised during an outdoor ceremony in Kharghar in Navi Mumbai, when the temperature reached 36 degrees Celsius.

INCREASINGLY, THE MOST common response has been the drafting of what is known as heat action plans (HAPs). Drafted by administrative units of cities, districts or states, these plans essentially serve as a plan for a region to deal with heatwaves, from when heatwave warnings should be issued, and identifying vulnerable populations, to preparing hospitals and other units.

Ever since the first HAP was introduced successfully in Ahmedabad in 2013, many other cities, districts and states have followed suit. However, many researchers have been highlight­ing the shortcomings of these plans. Last year, the think tank Cen­tre for Policy Research reviewed 37 of these plans and pointed out many of their flaws, from being too crisis-oriented and not having long-term solutions, lacking in funding, to not customis­ing plans to the local climate. For instance, the threshold at which heatwaves are declared is often based on levels prescribed by the India Meteorological Department and does not take into account factors like humidity. When the deaths occurred in Kharghar last year, according to reports, the temperature touched 36 degrees, a degree short of the prescribed point at which heatwaves are de­clared in coastal areas like Navi Mumbai.

A model heat action plan that resolves many of these issues, which was commissioned by the National Disaster Management Authority (NDMA) and which Kotharkar has been working on for several years, is now complete and has been presented at vari­ous government forums. This model HAP prescribes both im­mediate and long-term measures to combat heatwaves, and it is hoped that many administrative units will refer to it when adopt­ing new or updated HAPs for their regions. Kotharkar is aware that Nagpur Municipal Corporation, which she has worked close­ly with in dealing with heatwaves, from helping it issue heatwave warnings to guiding it to vulnerable localities where trees need to be planted, is adopting many of these measures.

Kotharkar has been studying heat, and in particular, the heat in Nagpur, which tends to be one of the areas that witnesses severe heatwaves in the country, for over a decade. An urban planner and architect by training, she says she was drawn into this field of heat research. “Initially, my work revolved around traditional housing typologies, and courtyard typologies, of Vidarbha [in Maharashtra] and I was wondering if these could be converted and used in today’s context,” she says. “Then, we really wanted to know more about outdoor thermal comfort. And then I realised that it has a major application in public health. Then the NDMA invited me to talk about my research in a workshop, so then it got this urban planning dimension.”

Kotharkar is a big advocate of not just coming up with local thresholds for issuing heatwave warnings, but also looking at microclimates within a city, instead of treating the entire city as a single entity. Kotharkar and her team have placed sensors across Nagpur to map how temperatures vary across a city and to look at how environments in specific areas affect temperatures. For instance, she has discovered that temperatures in the outskirts of the city, which is less dense and relatively greener, tend to be higher during the day compared to the city’s centre, which is more populated and has more structures, possibly because of the sun’s direct exposure on open land in the outskirts. During the night, this changes, with the city’s centre witnessing higher temperatures.

“The hypothesis is that cities have variable heat stress during the day and night, and areas that are experiencing heat stress or heatwave-like conditions during the day don’t need to be the same at night,” she says, pointing out how such information could help a city tailor its responses during a heatwave, from issuing warn­ings to focusing their efforts on more vulnerable locations. “So, for instance, when it comes to warnings, maybe in the mornings, you will have to warn people in the outskirts. And at night, you will have to warn people in the core area,” she says.

Kotharkar has also been involved in some fascinating heat studies. One of these involved finding out the outdoor thermal comfort point, or the neutral temperature where people feel nei­ther hot nor cold. This can help, she says, urban planners when they lay outdoor spaces like parks. Kotharkar and her team in­terviewed around 1,700 people across multiple locations over two-and-a-half months to find this temperature point. Another involved interviewing people to find out about their percep­tions of heat. Here, they interviewed somewhere between 400 to 460 individuals who worked outdoors, like auto-rickshaw drivers and vegetable vendors, who had a high exposure to heat. Although the temperatures sometimes touched 45 degrees Cel­sius, many often appeared nonchalant. Kotharkar is hesitant to draw conclusions, given the small sample size of the study, but one of the interesting discoveries she made, she says, is that individuals who had lived in warmer climates like Nagpur for several generations tended to be better equipped to deal with the heat than migrants from elsewhere. “Traditionally, when the mechanical means of cooling were not available, people made lifestyle modifications during summers, right from the kind of food that they ate, the amount of fluid intake, the kind of clothes they wore, the activities they were involved in and the timing of those activities. We observed that the people living in hot regions for a long time, say for a couple of generations, were aware of what needs to be done during summer. But the migrants who came from elsewhere were unaware and were most at risk,” she says.

Studies such as the one to determine the outdoor thermal comfort point are routinely done in the West but tend to be rare in India. But as heatwaves become more common and severe in the country, Kotharkar says, such studies, and interventions to tackle heatwaves, will become more common.

In Mumbai, Gilani says that of all the solutions they have come up with so far, the rooftop garden and the aluminium foil chain-sprocket have provided the best results, cooling many homes by several degrees. In all, they have come up with 25 solutions, each in various stages of completion. Many of the finished products are being further tweaked and improved upon.

Gilani and his team are currently in talks with civic authorities to have some of these solutions incorporated in HAPs, perhaps deployed temporarily as part of an annual drive before heatwaves, in the way civic authorities prescribe measures before a flood. In the near future, he hopes these solutions can be scaled up across several cities through cities’ electric utility-funded programmes and micro-business enterprises of women’s cooperatives.

Back in Pune, Yadav is talking about the benefits of his rooftop garden. Several neighbours have been pestering him, he says, to help them establish such gardens too. “It isn’t just that the sys­tem has cooled down my house considerably,” he says. “There are other benefits too. I’m now growing chillies, eggplants, and different types of greens.”

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