India's heatwave broke the planet's hottest city list. All 98 of them were in one country?

Step outside in India right now and the air does not greet you. It punishes you. From mid-April through May 2026, daily maximum temperatures crossed 46°C across large parts of the country, with some cities running 5 to 8 degrees above seasonal norms. Balangir in Odisha clocked 48°C. In late April, 98 of the world's 100 hottest cities sat inside India's borders. Not a handful. Not half. Ninety-eight.

And just as India broke under the heat, Europe followed. France reported fatalities. London logged what meteorologists call a tropical night, where temperatures refused to drop below 20°C. Scotland caught fire. The UK broke a century-old temperature record, then broke it again the very next day. This was not a regional weather event. This was a simultaneous, continent-spanning emergency, and climate change sat at the centre of all of it.

Why it got this bad

The immediate cause is high-pressure weather systems that settled over South Asia and refused to move. When these systems lock into place, they suppress cloud formation, shut out rainfall and trap hot air near the surface. The heat builds day after day with nowhere to go.

Behind the immediate mechanics, however, sits a larger and more uncomfortable truth. Gavin Schmidt, Director of the NASA Goddard Institute for Space Studies, puts the scale of what humanity has already done into stark perspective.

"We've warmed the planet by about 1.5 degrees Celsius since the 19th century, and that is halfway to the Pliocene," Schmidt said. "The Pliocene was the period 3 million years ago. That was the last time it was actually quite warm and that was only three degrees Celsius warmer than pre-industrial. So we're halfway there. But now in millions of years, in 150 years."

One hundred and fifty years to travel halfway to a climate that last existed three million years ago. That is the speed at which humanity has destabilised the planet.

What extreme heat actually does to people

The number on a thermometer tells only part of the story. Humidity tells the rest. The human body cools itself through sweat. Humid air, already saturated with moisture, slows evaporation dramatically. The body keeps heating. Core temperature climbs. Heatstroke sets in and without rapid cooling and urgent medical care, it kills.

For older people outdoors, 35°C combined with 90 per cent humidity is as deadly as standing in 45°C dry heat. Even healthy adults between 18 and 35 face mortal risk at 45°C with 40 per cent humidity. The heatwave claimed at least 37 lives in India and 10 in Pakistan, figures widely acknowledged to be significant undercounts.

The systems that buckled

India's peak electricity demand hit a record 270.8 GW on 21 May as millions reached for air conditioning simultaneously. Power outages followed. Water shortages gripped cities. Cattle died in Rajasthan. Road surfaces in Delhi reached 65°C. The infrastructure was not designed for this, because for most of its existence, it did not need to be.

No normal to return to

Perhaps the most chilling part of this crisis is the assumption that relief, when it comes, means a return to normal. Schmidt dismantles that idea entirely.

"There's no normal because that implies we're just going to stay where we are and we're not," he said. "Things are continuing to get worse. For us to stabilise global warming, even at the level it is now, effectively we have to get to net zero. We have to stop emitting carbon dioxide into the atmosphere. And that's a huge challenge. So that isn't going to happen any time soon. And so while that's not happening, temperatures are going to increase and the extremes are going to become more extreme."

He went further. "If you're making plans based on what extreme weather was doing in the 1980s, then you're way out of date with what's actually going to happen."

The numbers bear that out. At current warming levels of around 1.4°C, events like this hit South Asia roughly once every five years. The world tracks towards 2.6°C by 2100, at which point heatwaves of this intensity arrive every two to three years and run 2.2°C hotter.

Schmidt's final diagnosis leaves little room for comfort. "We still haven't really started reducing the amount of carbon dioxide in the atmosphere. And until we do, we have our foot on the accelerator pedal of global warming."

The monsoon will bring relief in June. But the accelerator is still down.