Nagendra Yadav has been working shirtless in a stuffy room at a fabric printing factory near India's industrial hub of Ahmedabad for years, but this summer the rising heat drove him to despair.

With May temperatures hovering over 40 degrees Celsius (104 degrees Fahrenheit) for more than two weeks in the region, and little respite from the heat since, the 32-year-old said his workplace — which has no fans or air-conditioning — has become a "furnace."

"Our endurance is tested everyday," said Yadav.