The hottest place in India, at 49.3 degrees (121 Fahrenheit), was Sri Ganganagar in the northern desert state of Rajasthan, with severe heat also prevailing in the adjacent states of Punjab and Haryana.
The federal health ministry does not regularly publish aggregated statistics of heat-related death tolls across states. CNN-IBN news channel on Thursday put the number at 134.
Streets were deserted this week as residents stayed indoors to escape the heat. But power cuts stopped ceiling fans, air conditioning and fridges, sparking protests in eastern regions.
"(The heat wave) is likely to subside in the next three to four days," B.P. Yadav, the spokesman for the India Meteorological Department (IMD), told Reuters. "The immediate cause appears to be the lack of thunderstorm activity."
Monsoon rains, which irrigate 60 percent of India's farms, are forecast to hit the mainland at the weekend, but have not advanced for the past six days, their progress slowed by last week's cyclone Laila.
While this year's rains are forecast to be normal, last year saw temperatures soar to the warmest year on record since 1901 and brought the driest monsoon in nearly four decades.
An official at London's Met office Hadley Center, said there was a "greater than 50 percent chance" that 2010 would be the warmest year globally on record.
New Delhi recorded its highest April temperature in nearly 60 years, according to the US-based National Climatic Data Center.
City doctors said they had admitted 10-20 percent more patients suffering from heatstroke than last year, according to the Times of India.
Residents poured into the air-conditioned metro in record numbers on Tuesday, the paper said, abandoning buses, taxis and auto rickshaws.
Officials in the eastern state of Orissa alone have confirmed 34 deaths from the heat wave since March, though authorities are investigating 65 more suspected deaths.
Thousands of protesters in the state blocked a main road on Wednesday to denounce power cuts.
Around 100 people have died in the western state of Gujarat, according to local media reports, but state officials released no figures.
