Dozens of monkeys in heatwave-hit India desperate for water have drowned in a well, a forest official said Tuesday, in a state where lakes have turned to dust.

Swaths of northern India have been gripped by a heatwave since last month, with temperatures soaring over 45 degrees Celsius (113 degrees Fahrenheit).

Last week, an Indian court urged the government to declare a national emergency over the ongoing heatwave, saying that hundreds of people had died during weeks of extreme weather.

The heat is also hitting wildlife, with animals searching for water in villages.

Nearly 40 monkeys drowned in the well in Palamu district of eastern Jharkhand state, where lakes have dried out in the heat, villagers said.

Kumar Ashish, the local government forest officer, said the troop had jumped in but could not escape.

"A team of forest officials are investigating," Ashish told AFP, adding that they were awaiting post-mortem results.

India is no stranger to searing summer temperatures but years of scientific research have found climate change is causing heatwaves to become longer, more frequent and more intense.

Researchers say human-induced climate change has driven the devastating heat impact in India and should be taken as a warning.