A scorching heatwave in two of India's most populous states has overwhelmed hospitals, filled a morgue to capacity and disrupted power supply, forcing staff to use books to cool patients, as officials investigate the number of deaths that has reached nearly 170.

In the northern state of Uttar Pradesh, 119 people have died from heat-related illnesses over the last several days while neighboring Bihar state reported 47 fatalities, according to local news reports and health officials.

"So many people are dying from the heat that we are not getting a minute's time to rest. On Sunday, I carried 26 dead bodies," Jitendra Kumar Yadav said, who is a hearse driver in Deoria town, 110 kilometers from Ballia.

Other residents said they were scared of going outside after midmorning.

The largest hospital in Ballia district in Uttar Pradesh is unable to accommodate more patients. Officials said the morgue was full after 54 people, all of whom were elderly suffering from various health issues, died during the heatwave. Some families were asked to take the bodies of their relatives home.

On Sunday, the state health minister, Brajesh Pathak, said a two-member team will look into what caused the large number of deaths and investigate how many of them are directly related to heat.

While northern regions of India are known for sweltering heat during the summer months, temperatures have been consistently above normal, according to the Indian Meteorological Department, with highs reaching 43.5 degrees Celsius. A heatwave is declared in India if temperatures are at least 4.5 degrees Celsius above normal, or if the temperature is above 45 degrees Celsius.

"We have been issuing heatwave warnings for the past few days," said Atul Kumar Singh, a scientist at the IMD.

Uttar Pradesh Chief Minister Yogi Adityanath said the government was taking measures to ensure an uninterrupted power supply. He urged citizens to cooperate and use electricity judiciously.

"Every village and every city should receive adequate power supply during this scorching heat. If any faults occur, they should be promptly addressed," he said Friday night in a statement.

Climate experts say that heatwaves will continue and India needs to prepare better to deal with their consequences. A study by World Weather Attribution, an academic group that examines the source of extreme heat, found that a searing heat wave in April that struck parts of South Asia was made at least 30 times more likely by climate change.

"Plans for dealing with heatwaves are essential for minimizing their effects and preserving lives. These plans include all-inclusive approaches to dealing with high heat occurrences, such as public awareness campaigns, the provision of cooling centers, and healthcare assistance," said Aditya Valiathan Pillai, an associate fellow at a New Delhi-based think-tank, Centre for Policy Research.

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