Reflective paint initiative helps to keep homes cool in India

As the sun reached its peak over India’s Ahmedabad city, Kajal Salat was busy stitching a tunic. A ceiling fan spun to keep the room cool, while a tiny window brought in daylight and fresh but humid air.

The 23-year-old seamstress has a pile of orders to finish.

A year ago, she almost quit her stitching job as she struggled to cope with the temperatures inside her single-room home in a slum in Ahmedabad. Located in Gujarat off the coast of the Arabian Sea, it is one of the hottest places in the world where temperatures reach up to 49ºC in summer.

However, a simple initiative by Mahila Housing Trust, a non-governmental organisation, to help her coat her roof with solar reflective paint, changed her life.

“It was difficult to work earlier because of the heat, but now, after the paint, the room is cooler,” Ms Salat told The National.

She said the women and children had to step out of their shanties and find refuge in the shade as men went to work.

“Now, I can work and finish the orders on time. I can sit in the afternoon and even in the evening and work extra hours to make extra money,” Ms Salat said.

Life-changing idea

The Gujarat government brought a heat action plan in 2013 to focus attention on those at risk during heatwaves and introduce early warning systems to minimise the damages, but several charitable trusts and non-governmental organisations are also working to protect the city’s most vulnerable people.

The Mahila Housing Trust initially experimented with waterproof modular roofs made of paper waste and coconut husks but switched to a cheaper, alternative of solar-reflective paint that helps bring down the temperature inside the shanties.

The paint is applied multiple times. While it has to be reapplied after a few years for efficacy, it is economical as it costs just 30 rupees ($0.36) per square foot.

It helps to bring down the temperature inside the shanties by 5ºC.

“In geographical areas where we have been working, temperatures range between 43ºC to 45ºC on certain days, but the feel is like 50ºC because of the kind of built environment,” Bijal Brahmabhatt, director of the trust, said.

“The roof is the most directly exposed element of a building to the sun. They have tin and asbestos cement sheets where the temperature is five to six degrees hotter inside as compared to outside. Solar reflective paint is applied to an existing roof to ward off the heat.”

The project started in 2017 and has since covered 20,000 houses in the city, providing some relief from the heat to more than 100,000 people.

The experiment is helping families comfortably spend time indoors during the summer, while allowing women to work and elderly and sick to rest at home, like Ratan Bai whose husband, Raju Bhai, 66, suffered a paralysis attack last year and has since been bedridden.

“My husband is paralysed. He cannot move. It was painful to watch him lying in the cot in this heat. The ceiling would throw hot air. But after the paint, it feels cooler inside. He can sleep in peace,” Ms Ratan Bai said.

Deadly heatwave

Summers in India are extreme and can be fatal when temperatures rise to 50ºC in several states.

Over 6,500 people in India have died between 2010-18 due to heatwaves, according to government data.

Ahmedabad witnessed one of the deadliest heatwaves in May 2010 when about 1,300 people were killed in a week after temperatures rose to 48ºC.

In 2022, India recorded the hottest April in 122 years.

The Indian weather office has warned of harsher days this summer as temperatures are set to soar by several degrees in May.

Last week, the government said at least 32 people died due to heatwaves in April this year across parts of central, southern and eastern India.

The excruciating heat has a detrimental effect on people’s health and productivity.

According to the World Bank, up to 380 million people, about 75 per cent of India’s workforce, depend on heat-exposed labour.

In a report, it said that India may account for 34 million projected job losses from heat stress-associated productivity decline by 2030.

Mrs Brahmabhatt emphasised that women are more prone to climate change-induced rising temperatures.

“When we started working on climate issues, we realised that India and largely the global south is also going to be subjected to heat as one of the main risks of climate change,” she told The National.

“We also understood that the poor, especially women, thought it was God's act. We understood that heat reduced their economic productivity by almost one-third. They had low incomes and would become lower in the hot season because of the amount of heat, which would make them uncomfortable.”