Temperatures in India's capital have soared to a record-high 49.9 degrees Celsius as authorities warn of water shortages in the sprawling mega-city.

The India Meteorological Department (IMD), which reported "severe heat-wave conditions," recorded the temperatures on Tuesday at two New Delhi suburbs stations, Narela and Mungeshpur.

The weather bureau said the temperatures were nine degrees higher than expected.

Forecasters predict similar temperatures Wednesday for the city of more than 30 million people, issuing a red alert warning notice for people to take care.

In May 2022, parts of New Delhi hit 49.2 degrees Celsius, Indian media reported at the time.

India is no stranger to searing summer temperatures.

But years of scientific research have found climate crisis is causing heatwaves to become longer, more frequent and more intense.

'Water scarcity'

New Delhi authorities have also warned of the risk of water shortages as the capital swelters in headache-inducing heat - cutting supplies to some areas.

Water Minister Atishi Marlena has called for "collective responsibility" in stopping wasteful water use, the Times of India newspaper reported Wednesday.

"To address the problem of water scarcity, we have taken a slew of measures such as reducing water supply from twice a day to once a day in many areas," Atishi said, the Indian Express reported.

"The water thus saved will be rationed and supplied to the water-deficient areas where supply lasts only 15 to 20 minutes a day," she added.

The IMD warned of the heat's impact on health, especially for infants, the elderly and those with chronic diseases.

Many blame the soaring temperatures on scorching winds from Rajasthan state, where temperatures on Tuesday were the hottest in the country, at 50.5 degrees Celsius.

Rajasthan's desert region of Phalodi holds the country's all-time heat record, hitting 51 degrees Celsius in 2016.

At the same time, West Bengal state and the northeastern state of Mizoram have been struck by gales and lashing rains from Cyclone Remal, which hit India and Bangladesh on Sunday, killing more than 38 people.

Bangladesh's Meteorological Department said the cyclone was "one of longest in the country's history", blaming climate crisis for the shift.