Heatwaves in India Are Becoming More Frequent and Dangerous: Report

From the Editor’s Desk

May 28, 2026

A new study analysed the hottest continuous 15-day stretch between April 15 and April 29 in parts of India and Pakistan to determine how much climate change influenced the event. While studying it, the researchers found that such prolonged heat events are now about three times more likely to occur and nearly 1°C hotter in today’s climate than they were before large scale industrial warming.

Many people imagine climate change as a slow increase in average temperatures over decades. While that is largely true, averages alone do not capture what people actually experience. Human beings feel weather through extremes, deadly afternoons, collapsing crops, nights that never cool down, overloaded electricity systems, dehydration, hospital emergencies and heat trapped inside homes. The bigger danger is that extreme events may become more frequent, more intense and longer-lasting.

The study by World Weather Attribution says that such a transformation is already happening in South Asia.

During this year’s heatwave, daily maximum temperatures crossed 46°C in several cities in India, especially northwestern parts of the country, and Pakistan. At least 37 heat related deaths were reported in India and 10 in Karachi, Pakistan. The study suggests that these numbers are likely underestimates because heat deaths are often hidden inside other medical categories like cardiac arrest, dehydration or kidney failure. The study also notes that agricultural drought conditions affected more than 1 million square kilometres during the 15 days. Electricity demand also surged across India because millions of households simultaneously needed cooling.

The researchers focused on two specific kinds of heat. One was the hottest single day in April. The second was the hottest continuous 15-day period in April. The 15-day category is especially important because long stretches of heat place enormous strain on the human body, agriculture, infrastructure and the economy.

One of the study’s most important findings is that the 2026 heatwave is no longer considered rare in today’s climate. The researchers estimate that the hottest 15-day period observed in April 2026 is now roughly a “1 in 5-year event.” In other words, there is now around a 20 percent chance of such heat occurring in any given year. A generation ago, many people would have regarded such temperatures as exceptional.

The study’s finding that human-caused climate change made the 15-day heatwave nearly 1°C hotter is significant. Many people think of one degree as a small difference between two comfortable room temperatures. In climate science, however, a rise of even 1°C means a place that earlier reached, for example, 44°C during a severe heatwave may now reach 45°C under similar weather conditions. That extra degree pushes more places into dangerous temperature ranges.

The study also examined how rapidly conditions are changing even over short periods. Comparing today’s climate with 2016, just 10 years earlier, the researchers found that similar 15-day heatwaves have already become around 35 percent more likely and about 0.3°C hotter.

The findings for single day heat extremes were even sharper. The researchers concluded that extremely hot single April days in the study region are now about 20 times more likely than they would have been in the pre-industrial climate. They also found these hottest days are now about 1°C hotter than before large-scale industrial warming.

The study repeatedly points to another critical trend. April heat is increasing faster than May heat. This means the dangerous heat season itself is expanding. South Asia is now entering periods of severe heat earlier in the year, well before the monsoon arrives. Researchers warned that people are increasingly facing a longer stretch of dangerous temperatures.

This affects agricultural cycles, schools, elections, census operations and any outdoor work, which continue under dangerous conditions because the traditional expectation of “peak summer” has not yet arrived psychologically or institutionally.

The study notes that India’s 2026 heatwave coincided with state assembly elections in several regions and with preparations for Census 2027. More than 3 million census workers, supervisors and officials were involved in outdoor activities during dangerous temperatures. The report argues that climate change is beginning to interfere directly with governance, public administration and democratic processes.

Another major point in the report involves humidity. South Asia’s warming patterns look slightly different from some other parts of the world. The study explains that atmospheric aerosols, pollution particles from vehicles, industry and burning fuels, along with widespread irrigation, may partially cool the land surface in some regions. But these same processes also increase humidity.

Humidity changes how heat affects the human body. Humans cool themselves mainly through sweating. But sweat works only when it evaporates. High humidity slows evaporation, meaning the body struggles to release heat. This is why a humid 40°C can sometimes become more dangerous than a dry 45°C.

The study warns that dangerous humid heat is rising rapidly across South Asia even where some temperature increases appear smaller than those recorded in Europe or North America.

The report also places enormous attention on inequality.

India and Pakistan together contain around 1.7 billion people. Large sections of the population work outdoors or live in poor quality housing with little cooling access. Construction workers, farmers, street vendors, sanitation workers, delivery workers and daily wage labourers face the highest risks because survival depends on continuing to work in the heat.

Indoor conditions can also become lethal. The study cites research from Pakistan’s Punjab region showing conventional brick and concrete houses crossing 45°C indoors during the hottest months. For poor families without air conditioning, heat exposure continues day and night.

Further, the report talks about the urban heat-island effect in cities like Delhi, Karachi and Mumbai. Concrete, asphalt and glass absorb heat during the day and release it slowly at night. Green cover has also shrunk as urbanisation has expanded. As a result, cities remain dangerously hot even after sunset, reducing recovery time for the human body.

The report argues that governments need to begin redesigning cities and infrastructure for a hotter future. That includes more trees and green spaces, reflective roofs, shaded public areas, improved ventilation, climate resilient housing and better urban planning. Heat resilience needs to become part of architecture, labour regulation, healthcare planning and energy policy.

Labour protection emerges as another major issue throughout the study. Outdoor workers increasingly need formal heat protections, access to water, shaded rest areas, flexible work schedules and legal safety standards during extreme heat periods.

Healthcare systems also need preparation. Heatwaves increase cases of dehydration, kidney stress, cardiovascular emergencies and heatstroke. Hospitals and ambulance services require advance planning during forecast heat periods. Electricity systems need upgrading as well because cooling demand rises sharply during heatwaves. Grid failures during extreme heat can quickly become deadly.

The study points out that heatwaves are often not officially classified as disasters in India and Pakistan. As a result, they frequently do not qualify for disaster relief funding.

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