Extreme temperatures can also impact economies (Representational)
The extreme heat crippling large parts of northwest India will continue for another five days, with Delhi, Haryana, Punjab, Rajasthan and Uttar Pradesh predicted to bear the maximum impact.
Swathes of north India stewed in brutal heat on Friday, with maximum temperatures soaring to a scorching 47.4 degrees Celsius in west Delhi's Najafgarh, the highest this season in the country so far.
The India Meteorological Department (IMD) on Saturday predicted severe heat wave over the plains of northwest India during the next five days and heat wave over east and central regions during the next three days.
The Met office also issue a "red" warning for Delhi, Haryana, Punjab and west Rajasthan, stressing the need for "extreme care for vulnerable people".
It issued an orange alert for east Rajasthan, Uttar Pradesh and Bihar and emphasised "high health concern" for vulnerable people, including infants, the elderly and those with chronic diseases.
In view of general elections in India, experts have warned of an increased likelihood of heat-related illnesses in people exposed to the sun for prolonged periods or engaging in heavy work.
A US-based group of climate scientists called 'Climate Central' said 543 million people in India will experience at least one day of extreme heat during May 18-21.
"Human-caused climate change has made this intense heat much more likely. The high overnight temperatures make this event particularly alarming," Andrew Pershing, VP for science at Climate Central, said.
Heatwaves can be deadly, with the elderly and children particularly at risk of heat exhaustion and heatstroke. According to the World Health Organization, more than 1,66,000 people died as a result of heatwaves between 1998 and 2017.
Extreme temperatures can also impact economies. People are less productive during hot weather, even if they work indoors, while children struggle to learn in extreme heat.
A study in 2022 said extreme heat resulted in labor productivity loss of USD 2.1 trillion equivalent in 2017.
On Friday, the maximum temperature surged to 47.4 degrees Celsius in Najafgarh and 47.1 in Haryana's Sirsa.
Before this, Kalaikunda in Gangetic West Bengal had recorded a high of 47.2 degrees Celsius on April 30.
The threshold for a heat wave is met when the maximum temperature of a weather station reaches at least 40 degrees Celsius in the plains, 37 degrees in the coastal areas, and 30 degrees in the hilly regions, and the departure from normal is at least 4.5 notches.
A severe heat wave is declared if the departure from normal exceeds 6.4 notches.
April witnessed record-smashing maximum temperatures in east, northeast, and southern peninsular India, prompting health warnings from government agencies and a few states to suspend in-person classes in schools.
Several places recorded their highest-ever April day temperatures, with the mercury soaring to 47 degrees Celsius.
At least two people died in Kerala due to suspected heatstroke during this period.
On Wednesday, a group of leading climate scientists said similar heat waves could occur once every 30 years, and these have already become about 45 times more likely due to climate change.
The scientists from the World Weather Attribution group emphasised that heat waves intensified by climate change are making life much tougher for people living in poverty across Asia.
The IMD had earlier warned of extreme heat in India during the April-June period, coinciding with the seven-phase Lok Sabha elections that end on June 1.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)