Eastern India experienced its hottest April on record. (File)
Several parts of India grappled with unusually high temperatures this week, forcing schools to close and hospitals to create special units to treat heat-related illnesses, while workers on construction sites were given a "paid holiday" in the afternoon.
Here is a look at what caused the unprecedented heat in the country.
HOW UNUSUAL HAS THE SITUATION BEEN THIS YEAR?
While every year temperatures in India tend to peak in the months of May and June, the number of heatwave days recorded over northwestern and eastern parts of the country this season have been more than double the normal, with eastern India also experiencing its hottest April on record.
India declares a heatwave day when the maximum temperature in any given region is 4.5 -6.4 degrees Celsius higher than normal.
Parts of the country have touched new highs in terms of the maximum temperature, including Delhi, which recorded the country's highest ever temperature at 52.9 C (127.22 degree F) on Wednesday.
While this figure may be revised as officials are investigating whether it was caused by an error in the sensor, two areas in Delhi also recorded 49.9 C a day earlier - an all-time high for the city.
In northern Haryana state, which surrounds Delhi from three sides, the Rohtak region recorded its highest-ever temperature on Friday at 47.5 C.
WHY HAVE TEMPERATURES RISEN THIS SEASON?
Scientists from India's weather department said that while a rise in temperatures during May and June is normal, it is usually controlled by periodic western disturbances, which are weather systems originating in the Mediterranean Sea that bring moisture-laden winds.
These neutralise the impact of the hot, dry air coming from the direction of Pakistan and Afghanistan into northern India.
This year, however, there were more western disturbances between March and early May than usual, while their strength has reduced over the last "10-15 days", leaving the wind coming from neighbouring countries unchecked and causing temperatures to rise.
Global and India-based experts say such weather changes are being worsened by human-driven climate change.
WHY IS THE SITUATION IN DELHI PARTICULARLY BAD?
Surrounded by alluvial plains in the north and east, the Thar desert in the west, and the Aravalli hill ranges in the south, Delhi, with a population of about 20 million, is one of India's fastest-growing areas.
Officials and experts say apart from its location, the capital is also particularly vulnerable because of its large population, scattered vegetation, and increased construction in the last two decades, with the built-up area increasing from 31.4% in 2003 to more than 38% in 2022.
WHEN WILL THE HEAT ABATE?
According to the India Meteorological Department, the temperature in northwest, central, and east India will gradually decline over the next three days because of the impact of the approaching western disturbance, rainfall, and the southwesterly wind blowing from the Arabian Sea.
Monsoon rains reached the southernmost state of Kerala on Thursday, bringing relief to residents there.
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