© Money Sharma/AFPA woman shields her child from the sun during a heat wave in New Delhi on Wednesday.
A heat wave alert has been in place for large parts of India since last week but on Wednesday the temperature in Mungeshpur, a densely packed corner of Delhi, crossed the 50 C mark, the weather office said.
The Indian capital has had temperatures of over 45 C in previous years but never gone as high as 52.9 C.
Streets in Mungeshpur in northwest Delhi were deserted and most shops were shut as people stayed indoors to avoid the searing heat, while residents handed out free cold drinks in Narela after temperatures went up to 49.9 C on Tuesday.
"When we go outside it seems like someone is slapping our faces. It has become difficult to live in Delhi," said resident Akash Nirmal.
India Meteorological Department (IMD) said it is examining the data and sensors to look into Mungeshpur's temperature which was an outlier compared to other stations.
"There is so much heat in Delhi that students are fainting, some are falling sick, some are facing dehydration. The students are facing a lot of trouble in this heat. The fans don't work in our institutions," said Nidhi, a student, who gave only their first name.
An unusual transition from El Nino to La Nina and the lack of winds bringing moisture, has resulted in prolonged heating, leading to record temperatures, Gufran Beig, chair professor at the Indian Institute of Science told Reuters.
El Nino is the warming of Pacific waters that is typically accompanied by drier conditions over the Indian subcontinent while La Nina is characterised by unusually cold temperatures in the Pacific Ocean.
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In the Okanagan, 2 years ago, it went to 46 C. That was unbearable. Anything after 36 C, it gets difficult to breathe.