Eating onions, lying in the shade and crowding into rivers, Indians are doing whatever they can to stay cool amid a brutal heatwave that has killed more than 1,400 in the past month.

Officials say most of the 1,412 deaths have occurred in the southern states of Andhra Pradesh and Telangana, where temperatures have soared to 47C.

Officials are warning people to stay out of the sun, cover their heads and drink water. Doctors are on alert for heat-related illness, while volunteers are distributing salted buttermilk or raw onions - both thought to be hydrating.

Meteorological officials say the heat will likely continue for several more days, warping roads, scorching crops and endangering construction workers, farmers and anyone else labouring outdoors.