Four men collapsed and died at a train station in Kanpur on Tuesday in a heat wave that has killed more than 200 people across India, but monsoon rains have started bringing relief to some areas, news reports said.
India's dry summers often bring deadly heat. This year, temperatures have soared up to 50°C in some areas.
Thirty two people have died due to the heat wave in neighboring Bangladesh.
Most of the dead were elderly people, young children and the poor, who often lack proper shelter and adequate drinking water, officials said. The sweltering heat has been worsened by power cuts that disable fans and water pumps.
However, some sections of the Indian media have said the toll could be higher. The NDTV news channel reported on Tuesday that up to 380 may have died. There was no official confirmation of the higher number.
Temperatures have eased in the past week in Bangladesh with the onset of monsoon rains on June 14. In India, the rains are slowly sweeping northward towards parched areas.
On Monday, rain cheered millions in Mumbai.
Meteorologists said India's temperatures were unusually high for June.
A passenger was found dead due to the heat wave on a railway platform in Kanpur on Monday, PTI said.
However, an overnight drizzle dropped Kanpur's temperature to 41°C on Tuesday from 46°C on Monday. Similar drops were reported in other cities.
Purulia, in the eastern state of West Bengal, was reported to be this season's hottest place in India last week with 51.1°C on Sunday. It cooled to 42°C on Tuesday after intermittent rains, PTI said.
About half of India's heat wave deaths this year have been reported in the eastern state of Orissa, where temperatures in the Angul district touched 50°C, state officials said. The affected area is about 170 km west of the state capital Bhubaneswar.