By Meryl Sebastian and Kathryn Armstrong, BBC
Parts of northern and central India are sweltering under a severe heatwave, with a provisional record temperature of 52.3C registered in Delhi.
If verified, it would be the highest ever recorded in India.
More than 37 cities in the country recorded temperatures over 45C this week.
Warnings of heat-related illnesses have been issued, with at least three deaths reported so far.
The India Meteorological Department (IMD)'s Soma Sen Roy told the BBC that a team had been sent to the Mungeshpur area in Delhi - where the 52.3C temperature was recorded - to verify it.
The IMD described the recording as an "outlier compared to other stations", which had recorded temperatures ranging from 45.2C to 49.1C in different parts of Delhi.
The city's authorities have warned they will issue fines to those caught wasting water as the city deals with shortages and supplies have been cut to some areas.
Water minister Atishi announced that 200 teams would be deployed to crack down on people washing their cars with hosepipes and letting their tanks overflow.
"It's been excruciatingly hot over the past couple of days and it's got significantly worse as the days progress," said BBC Business Correspondent Arunoday Mukharji, who is in Delhi.
A resident told news agency ANI earlier in the week that it was difficult to even eat properly because of the heat.
"We have faced heat earlier as well, but this time it feels unbearable," they said.
"It's difficult to even stand outside."
The city's power demand has soared to an all-time high, with residents turning to air conditioning, coolers and ceiling fans to cope with the heat.
A consumer court stopped hearing cases on Tuesday after the judge said it was too hot to work without air conditioning.
Red alerts have been issued for several parts of India's north-west, including Delhi - meaning there is a very high likelihood of people developing heat illness and heat stroke.
Dr Chandrakant Lahariya, a family doctor in Delhi, told the BBC World Service that medical consultations had increased during the heatwave.
He said the impact of the high temperatures was worse in elderly people who have pre-existing conditions, as well as "some of the poorest and migrant workers who are working in the construction sites and other places".
Delhi's lieutenant governor has ordered that workers at construction sites be given a three-hour paid break and asked for water to be provided to them.
He has also asked for pots with drinking water to be provided at bus stands.
IMD regional head Kuldeep Srivastava said the reason behind the rising temperatures in Delhi was the arrival of hot winds from the state of Rajasthan.
Elsewhere, the cities of Churu in Rajasthan and Sirsa in the northern Haryana state have recorded temperatures over 50C.
Rajasthan's Jaipur city reported three deaths due to heat stroke on Tuesday.
Several students were rushed to hospital in the town of Sheikhpura in the eastern state of Bihar after fainting due to the high temperatures, local media reported.
In Indian-administered Jammu and Kashmir, efforts are continuing in to tackle a number of forest fires that are being fuelled by the heat.
According to IMD chief Mrutyunjay Mohapatra, maximum temperatures are likely to remain above normal in June.
He added that northwestern India is expected to see heatwave conditions for four to six days.
Indian summers, which extend from March to September, are usually hot and humid.
But the weather department has said the country is likely to experience longer and more intense heatwaves this year.
This month, the states of Rajasthan and Gujarat saw nine to 12 days of heatwave, with temperatures between 45-50C, it said.
Scientists have said global warming has made extreme heatwaves in India much more likely.
In Delhi, construction, traffic and a lack of green spaces have added to the problem.
The extreme heat comes as coastal parts of eastern India and southern Bangladesh were hit by Cyclone Remal - killing dozens of people.
Meanwhile, the IMD has also predicted an above-average monsoon season for the country this year.
The monsoon is forecast to hit the coast of the southern state of Kerala on 31 May.
- BBC