Hundreds of people, mostly from poorer sections of society, die at the height of summer every year across the country, while tens of thousands suffer power cuts from an overburdened electricity grid.
"The kind of heatwave we are seeing now is slightly higher than normal. The temperatures here have almost touched 48-49 degrees Celsius," Telangana revenue secretary BR Meena said.
Poorly paid workers said they could barely afford to heed the warnings to stay at home to avoid the worst of the heat.
"I am a diabetes patient, but I have no husband and no sons, so I have to stay here and keep shop," said P Gangamma, 65, who runs a cigarette stand at a busy intersection in Telangana's capital, Hyderabad.
Gurunath Patil, who plies his auto rickshaw in the capital eight hours a day, said "you can't make money sitting at home".
Several deaths have also been reported in the north-western desert state of Rajasthan in recent days including a woman who collapsed and died on the roadside in Bundi city, the Press Trust of India said.
In the eastern city of Kolkata, taxi unions have urged drivers to stay off the roads between 11:00am and 4:00pm because of the heat.
India's weather bureau warned that "heatwave to severe heatwave conditions would prevail" in Andhra Pradesh and Telangana in coming days as well as in the northern states and New Delhi.