A brutal pre-monsoon heatwave pushed temperatures above 46 degrees Celsius across northern India and eastern Pakistan on Wednesday, killing at least 73 people in three days, forcing rolling blackouts in four Indian states and shutting schools from Karachi to Patna as electricity demand on the regional grid breached records set only last summer.

The India Meteorological Department in New Delhi said the Safdarjung observatory recorded 46.2 degrees Celsius shortly after 3 p.m. local time, the capital’s highest April reading since 1944 and within striking distance of the all-time April record of 46.7. Stations in Nagpur, Jhansi and Ganganagar all crossed 47 degrees, and a “severe heatwave” advisory now covers a swath of territory stretching from Sindh in southern Pakistan across Punjab, Haryana, Delhi, Uttar Pradesh and into Bihar.

“What we are seeing is the third consecutive April in which the pre-monsoon ridge has parked itself over the Indo-Gangetic plain earlier and more intensely than the climatological mean,” said Dr. Sunitha Devi, additional director general of meteorology at the IMD, in a briefing at the agency’s Lodi Road headquarters. “This is not a record-shattering event in isolation. It is a record-shattering pattern, and the pattern is what hospitals and power planners have to design for now.”

Hospitals in Delhi, Lucknow and Lahore reported the bulk of the confirmed deaths, most of them outdoor laborers, rickshaw pullers and elderly residents in neighborhoods without reliable electricity. The Pakistani health ministry in Islamabad said 31 deaths had been recorded in Punjab and Sindh provinces since Sunday, with at least 12 occurring in Karachi, where a humid heat index pushed apparent temperatures above 49 degrees. India’s National Disaster Management Authority put its own three-day toll at 42 across eight states but cautioned that under-reporting in rural districts was likely.

Power demand surged in tandem. India’s national grid operator, POSOCO, said peak demand crossed 252 gigawatts on Tuesday evening, eclipsing the previous all-time high recorded last June and triggering scheduled load-shedding across parts of Bihar, Jharkhand, Uttar Pradesh and Andhra Pradesh. Officials said the country was importing emergency power from Bhutan and had asked aluminum smelters in Odisha to curtail operations during evening peak hours. In Pakistan, the National Transmission and Despatch Company said outages of four to eight hours had returned to most secondary cities for the first time since the winter, with industrial feeders bearing the brunt.

“The grid is holding, but it is holding by giving people in smaller cities a much worse summer than people in the metros,” said Rohan Krishnan, a senior fellow at the Council on Energy, Environment and Water in New Delhi, by phone Wednesday evening. “And every degree above the long-term mean adds roughly six to eight gigawatts of cooling demand that we did not have at the start of the decade. The math of that catches up with the infrastructure very quickly.”

Authorities across the region scrambled to adjust public services. The Delhi state government ordered all public and private schools closed through May 6 and pushed the start of the day for outdoor municipal workers to before sunrise. Punjab in Pakistan announced a similar shutdown of schools and a ban on outdoor exam centers until temperatures eased. Indian Railways said it had installed additional water points at 140 major stations and was running extra cooling cars on long-distance trains in the affected corridor.

The heat is also rattling the agricultural calendar. Officials at the Indian Council of Agricultural Research said the late-season wheat harvest in Madhya Pradesh and southern Uttar Pradesh was being brought in roughly ten days ahead of normal to limit grain shriveling, while mango orchards across the Lucknow belt were reporting heavy premature fruit drop. In Pakistan, growers in Multan said cotton sowing had stalled because field temperatures were too high for safe germination in unirrigated plots.

The South Asian heatwave is unfolding alongside a separate, less severe but still acute hot spell across the Persian Gulf, where forecasters in Dubai and Doha said temperatures had brushed 44 degrees this week, complicating the still-young reconstruction effort in southern Iraq and the Iranian provinces of Khuzestan and Ilam. Returnee transit camps along the Iran-Iraq corridor, already under strain from a cholera outbreak that has killed at least 30 people since the weekend, have asked the United Nations for additional shaded shelter, electrolyte supplies and tankered water.

“We are watching two heat domes, one over South Asia and one over the lower Gulf, and they are reinforcing each other through the upper-level pattern,” said Dr. Anjali Prakash, a climate attribution researcher at the Indian Institute of Science in Bangalore who has co-authored rapid analyses of South Asian heatwaves for nearly a decade. “Without the warming we have already locked in, an event of this magnitude this early in the season would be roughly thirty times less likely. With it, it is becoming something close to a regular feature of April.”

The Indian central government convened an inter-ministerial review chaired by the cabinet secretary on Wednesday afternoon and authorized the release of emergency funds to states under the National Disaster Response Fund’s heat-action allocation. Officials said additional measures, including possible directives on construction-site working hours and expanded cooling-center deployments in Tier-2 cities, would be announced once state-level requests had been consolidated.

Forecasters offered only modest relief in the short term. The IMD said a weak western disturbance approaching from the northwest could bring dust storms and isolated thundershowers to parts of Punjab and Haryana late Friday, briefly knocking maximum temperatures down by two to four degrees, but said the broader heat dome was likely to reassert itself over the weekend and persist into the first week of May. The southwest monsoon’s onset over Kerala remained on its long-term schedule for the first week of June, leaving more than a month of pre-monsoon conditions still to run.