Intense summer heat is not new for Indians. But the searing heat that one feels now, both during the day and at night, is certainly something that Indians have rarely experienced before. Day temperatures of 40 degrees Celsius and more, particularly in northern India, do make headlines, but what cannot be ignored is that nights are no longer sufficiently cool for the body to recover and restore its equilibrium. Equally concerning is the narrowing of the difference between maximum and minimum temperatures, which makes summer feel like a terribly hot and humid season long after the sunset.
What is unusual about this year’s summer, or the recent ones, is the gradual departure from the earlier pattern of summer heat—hot and humid afternoons, followed by a gradual decline in temperature towards the evening. This old rhythm of hotter days, softer evenings and cooler nights seems to have broken down. Whether in cities or smaller towns, there is no respite from heat, even after midnight, depriving bodies of recovery from persistent hot weather conditions, thus affecting sleep and increasing health risks. The unusual hot spell has several implications for individual health, livelihood, and the economy.
Last week, it was reported that fifty of the world’s hottest cities were in India, with the heatwave unlikely to soften till the next week, especially in the northern, western, central, and eastern regions. What’s more discomforting is the fact that the summer has been longer this year, with hot conditions setting in early and heatwaves observed in March itself. This has badly affected many people in urban and rural areas, who have to work and move in the open spaces—farmers, construction workers, street vendors, logistics agents, and many others. The poor are the worst hit, given their difficult living conditions—water shortages, power cuts, and inadequate housing and shelter.
The impact of heat on the poor and vulnerable sections of society cannot be understated: sustained heat exposure, according to experts, has several implications, amplified by urban factors like social inequality, urban design failures, energy shortages, and an unrelenting hot climate. According to the Indian Meteorological Department (IMD), India’s night temperatures are rising by around 0.21 degrees every decade. This means heatwaves are not just about temperatures but also about environment, climate change, disappearing forests, concrete roads, glass buildings, and the relation between human lives and nature. The more you play with nature and ecological balance, the more severe the impact on the environment, trees, animals, birds, and humans.
In 2022, the World Bank had said that about three-fourths of India’s labour force worked in heat-exposed sectors, which may have accounted for nearly half of the world’s projected job losses caused by heat stress. The World Bank had also warned that heatwaves can cost India about 4.5 per cent of its GDP by 2030. In other words, the economic impact of heatwaves and hot weather conditions is quite high in a poor country like India, where more than half of the population survives on bare minimum wages and earnings through odd and casual jobs. The challenge before the country, therefore, is no longer only the summer heat but sustained heat exposure, hot days, and warm nights.
While debates and discussions on heatwaves often revolve around high afternoon temperatures, the night temperature is usually not given enough attention, though hot nights are equally dangerous, as they disturb sleep cycles and heighten the risk of heat exhaustion. Loss of sleep causes the risk of impacting immunity, concentration, productivity and mental health. According to experts, the body regulates internal temperature through sweating and increased circulation during the day while it relies on cooler nights to restore the body’s temperature balance. But warm nights weaken the body’s recovery mechanism.
Heatwave alerts from the IMD often focus largely on maximum daytime temperature, which, experts say, does not capture the real scale of the risk since night temperature, humidity, and the duration of exposure to heat are equally important in public advisories to make people aware of the cascading effects of excessive high temperatures. Heatwaves are not just an urban phenomenon, but the acceleration of urbanisation, migration, and concentration of population in cities because of employment opportunities has made India’s big cities major reservoirs of heat. Dense construction, road widening, loss of green spaces, low tree cover, concrete roads, and disappearing lakes, ponds, and wetlands that moderate heat have made cities into major contributors to their own heat burden.
The problem with urban planning in India, city planners and climate experts say, is that high temperatures and humidity in urban centres are treated as a seasonal inconvenience and not a structural design issue to tackle hot and humid weather conditions. Just as transport, drainage, waste disposal, cleanliness, water supply, pavements, gardens, and children’s parks are vital to city planning, equally fundamental is weather comfort. Heatwaves may be environmental events caused by rapid urbanisation and climate change, but intense heat and humidity have an adverse effect on health and the economy, as the overall economic activity slows down and inflation spikes after a sustained hot spell.
While the forces of climate change have added to India’s sweltering summers and generally warm weather, blaming climate change as a fait accompli for heatwaves and sustained high temperatures in urban India is a lame cover for lack of a heat action plan and to avoid responsibility for governance for a cooler environment. Environment experts are of the view that it is not India’s geographical position or any special climatic situation that is responsible for making India the world’s heat capital. It is the lack of planning, stripping of forests, flattening of hills for development, denudation of forests, destruction of vegetation, and degradation of lakes and water bodies that have contributed to the change in climatic conditions.
Once summer arrives, temperature rises significantly, but when nights refuse to cool, it indicates that we need to develop a long-term heat action programme to address the root causes of the worsening heatwave conditions. Soon, rains will bring some temporary relief from the scorching sun, but relief is not a solution to a problem that will visit again next summer.
The writer is a senior independent Mumbai-based journalist. He tweets at @ali_chougule
