There have been some dire predictions about how hazardous the heat is going to be this summer. India this year experienced its warmest February since 1877, and in November last year, the World Bank warned that India could become one of the first places in the world where wet-bulb temperatures could increase beyond the survivability threshold of 35°C. Furthermore, last month, Peter Dynes, chief strategy officer at Mirrors for Earth's Energy Rebalancing (MEER), tweeted that India this summer is at “serious risk of wet-bulb” if global temperatures continue to rise. So, what exactly is the wet bulb phenomenon, and what does it mean when it is said that summer temperatures in India could cross the wet bulb threshold? Have heat wave conditions in India worsened due to climate change? What should we be doing to mitigate the effects of heat wave conditions and protect the most vulnerable?