Extreme heat in India has killed more than 100 people in the past three and a half months

A monthslong heat wave across swathes of India has killed more than 100 people and led to over 40,000 suspected cases of heat stroke in the past three and a half months, according to data from India's Health Ministry.

Between March 1 and June 18, 110 people in India died after suffering heat strokes, according to Health Ministry data provided to The Associated Press. Officials from India's Health Ministry and its subsidiary body, the National Centre for Disease Control, which compiled the figures, declined to comment.

The highest number of deaths — 36 — were reported in Uttar Pradesh state, followed by other northern states including Rajasthan, Bihar and Odisha, which has borne the brunt of the extreme weather. The data also showed that of the 40,272 cases of suspected heat stroke during this period, 457 were reported on Tuesday.

The capital, New Delhi, has also been gripped by extreme heat even as brief rains and winds on Thursday morning cooled temperatures after the city suffered its hottest night in over five decades earlier this week. The country's weather department expects some respite from the heat over the next few days, but said extreme weather could continue after that.

India declares a heat wave whenever temperatures are above 40 degrees Celsius (113 degrees Fahrenheit) in the plains and 30 degrees Celsius (86 degrees Fahrenheit) or more in its hilly regions.

In recent weeks, parts of the capital reported temperatures up to 51 C (123.8 F), triggering record demand for electricity and leading to frequent power cuts in the city, which is also battling a severe water crisis.

A number of places in northern India, where soaring temperatures have broken records, have also been forced to shut schools due to the heat.

On Wednesday, Health Minister J P Nadda directed authorities to set up special heat wave units in federally run government hospitals to help patients who fall ill due to the heat.

The main summer months — April, May and June — are always hot in most parts of India before the monsoon rains bring cooler temperatures.

But the heat has become more intense in the past decade and is usually accompanied by severe water shortages, with tens of millions of India's 1.4 billion people lacking running water.

Climate experts also say that extreme heat in South Asia during the pre-monsoon season is becoming more frequent. A study by the World Weather Attribution, a climate impact monitoring agency, found that a searing heat wave in April in parts of Asia was made at least 45 times more likely in some parts of the continent by climate change.

According to India's weather agency, this year's heat wave, which has continued for more than three weeks, is likely among the longest continuous heat spells the country has ever experienced.

Last year, more than 150 people died in India during heat waves. The government estimates nearly 11,000 people have died in heat waves this century, but experts say such figures are likely a vast undercount, since the lack of an efficient system to document heat-related illness and deaths remains a major issue.

"We don't classify and measure deaths as much as we should and that is one reason why heat-related deaths are difficult to count," said Dileep Mavalankar, former head of the Indian Institute of Public Health in Gandhinagar.

Mavalankar was instrumental in developing India's first heat action plan for the city of Ahmedabad in 2013, three years after more than 1,300 people died there during a heat wave.

Many heat deaths are also counted as deaths by other comorbidities, according to Mavalankar.

"Not only during heat waves but even in general, we need to be counting deaths better. That is the only way we will know how severe the consequences of extreme heat are," he said.

India, the world's most populous country and one of the world's largest emitters of planet-heating gases, is among the most vulnerable to climate impacts. A report by the New Delhi-based Centre for Science and Environment found that the country experienced extreme weather on nearly 90% of the days last year.