Delhi records warmest night in 12 years. What's causing the rise in mercury?

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Moreover, police in the adjoining Noida found seven people dead in different parts of the city in the last 24 hours without any visible signs of injury.

Between March and May, the sweltering heat has claimed at least 56 lives, PTI had reported earlier this month, citing a government data.

Boiling hot water from taps during the nights is not even a surprise anymore.

What leads to jump in night temperatures?

One of the biggest reasons for the surge in night temperatures is the increase in concrete structures in cities. Concrete buildings absorb heat during the day and release it at night, Rajneesh Sareen, who  leads the Sustainable Habitat Programme at Delhi-based think tank Centre for Science and Environment, told NDTV.

ALSO READ: India's 'heat trap' cities make summers worse, says government official

Millions of people across Asia are grappling with extreme heat this summer, in a trend that scientists say has been worsened by human-driven climate change.

Since March, temperatures have soared to 50 degrees Celsius (122 degrees F) in Delhi and Rajasthan, while more than twice the usual number of heatwave days were recorded this season in the country's northwest and east.

In Rajasthan’s Alwar, night temperatures touched 37 degree Celsius for two consecutive days this week, the highest in records dating back to 1969, according to India Meteorological Department.

What are warm nights?

The weather department declares warm nights when the maximum temperature during the day is over 40 degree Celsius and the night temperature is 4.5 degree Celsius or more above the normal.

What is the human impact of rising mercury?

One of the most dangerous impacts of global warming is that temperatures are rising at night, denying people the ability to cool off during heat waves. Hotter nights increase health risks to those without access to air conditioning, while putting a strain on the grid due to the absence of solar output after sunset.

Warmer nights deprive people of the chance to recover from working during the day-time heat, according to Avikal Somvanshi of New Delhi-based Centre for Science and Environment. “This inability to cool down at night has only worsened in recent years.”

When can we expect some relief?

Heat wave is expected to continue for another day and gradually start abating thereafter, the weather office said on June 19. Thunderstorm and light rain are expected on June 20 and 21.

"A western disturbance seen as a cyclonic circulation lies over north Pakistan and neighbourhood in lower and middle tropospheric levels. Under its influence, isolated to scattered light rainfall with thunderstorm, lightning and gusty winds (30-40 kmph) is very likely over Jammu-Kashmir-Ladakh-Gilgit-Baltistan-Muzaffarabad, Himachal Pradesh, Uttarakhand during 19th-23rd and over Punjab, Haryana-Chandigarh-Delhi, Uttar Pradesh and Rajasthan during 19th-21st June, 2024," it said.

However, the Delhi could see heatwave conditions return during the weekend and the beginning of next week with mercury rising to 45 degree Celsius, according to IMD.

Power blackouts

Frequent blackouts, crowded hospitals and water shortages have sparked protests in India. In capital New Delhi, water supply is being rationed in several areas, including the tree-lined enclaves inhabited by the nation’s top lawmakers and business tycoons.

Massive consumption of electricity amid a punishing heat wave sustaining over weeks pushed peak power demand of Delhi to an all-time high level of 8656 MW on June 19 afternoon, discom officials said.

The peak power demand was on June 18 recorded at 8647 MW, the second highest in this summer season.

According to the real-time data of State Load Dispatch Centre (SLDC) Delhi, the peak power demand reached 8656 MW at 15:06:55 hrs on June 19. The surging demand has pushed the power system to its limits, forcing intermittent outages.

(With agency inputs)