In May 2022 temperatures in Northern India hit 49°C. The Indian Meteorological Department declared it a ‘heat wave’ and in a heat wave, public infrastructure begins to fail: pavements buckle, railway tracks warp, and electrical grids are strained by increased use of air conditioning. Fires start in dry fields. Industrial plants require more water for their cooling systems, straining already reduced supplies. Crops are ravaged. A heat wave is also a national health emergency. At a wet-bulb temperature of 35°C – that is, the equivalent of 35°C and 100 per cent humidity – the human body can no longer cool itself by sweating. You overheat and die within hours. Throughout May, regions across India saw consistent wet-bulb temperatures between 25 and 33°C.


