Written by Himanshu and Zerin Osho
Europe witnessed its deadliest heatwave in June, with France, Belgium and the Netherlands recording 3,700 excess deaths. The heatwave, which lasted between June 20 and 28, was among the worst-recorded in Europe, saw rising temperatures cause disruptions to power supply and infrastructure damage, while overwhelming the healthcare system. Scientists have attributed the extreme heat almost entirely to climate change.
The US, currently a co-host of the ongoing Football World Cup, is also in the midst of a heatwave that scientists have attributed to a heat dome, causing warm air to be trapped in the atmosphere for a prolonged period. At least 25 people have died over the Fourth of July weekend, while over 20 states experienced temperatures exceeding 38°C.
The heatwaves have spurred comparisons with India, where heatwaves are more frequent, longer-lasting and expose hundreds of millions of people each year. Yet unlike Europe, which estimates excess deaths during extreme heat events, India still lacks a comprehensive system to measure heat-related mortality, leaving the true human cost of rising temperatures largely unknown.
Why is heat mortality difficult to measure and track accurately in India? What do current estimates likely miss?
Heat is seldom recognised as a cause of death and rarely appears on a death certificate. This is chiefly because heat is treated as a contributing factor, not as a cause. People who die of heat generally suffer from other underlying illnesses or co-morbidities, and heat acts as a hidden trigger, exacerbating these problems. So when extreme heat strains a weak heart, the recorded cause is a heart attack.
The bare-bones definition of heat mortality is one critical source of confusion. Currently, the official data only counts heatstroke deaths and not the broader category of ‘heat-related’ deaths. Separately, official data does not account for undigitised records and excludes data from the private health sector, which delivers nearly two-thirds of all inpatient care. Therefore, current estimates exhibit large variation due to fragmented sources, each with its own definition of heat mortality.
Tracking data accurately, and juxtaposing heat-related deaths to temperatures on a particular day could help build an evidence base for policymakers to design tailor-made heat management solutions that reduce heat mortality.
There is a common perception that Indians are more accustomed to extreme heat than Europeans. From a public health perspective, how true is that? Does living in a hot climate protect people from the health risks of prolonged heat exposure?
This perception is not entirely true. Indians have not evolved to become biologically accustomed to heat; however, they have become better adapted to it.
India has historically been hot. Therefore, habits and infrastructure have evolved around heat being an integral part of Indian lives. This includes ventilated architecture, coolers, fans, widespread air-conditioning, and traditional evaporative cooling methods such as clay matkas.
Europe, on the other hand, was never built for heat, and temperature is now rising faster than it can adapt. This is why European heatwaves have proven deadly.
Biological evolution by itself offers limited protection against heat. Pertinently, absolute temperature does not depict the full picture, which is why forecasts now report a “feels like” temperature.
One such factor is the “wet-bulb” temperature. This temperature tracks humidity alongside heat. Sweating, the body’s natural cooling mechanism, must evaporate to cool. Increased humidity reduces this evaporation. Therefore, the same temperature is far more dangerous on a humid coast than in a dry environment. Irrespective of acclimatisation, prolonged exposure to wet-bulb temperatures above 35°C can prove fatal.
Who are the Indians most vulnerable to extreme heat today? Are there particular occupations, age groups, income groups, or regions that face disproportionate risks, and why?
The occupational groups most at risk are outdoor workers who are directly impacted by any increase in temperature. Farmers, construction workers, manual labourers, street vendors and delivery riders are most vulnerable. Making matters worse, such workers belong to lower-income groups and work in the informal sector and fall beyond the purview of protection measures. Consequently, with no paid sick leave and unable to afford a day’s lost wages, such workers are forced to work through dangerous heat with no protection.
Research suggests other demographics which face disproportionate risks of heat mortality are infants, the elderly, pregnant women and people with chronic illnesses.
Geography concentrates the danger. A 2026 mortality study found that five states—Uttar Pradesh, Bihar, Madhya Pradesh, Rajasthan and Gujarat—account for more than 60% of estimated heatwave deaths. Poverty runs through all of it: those who cannot afford cooling or rest bear the greatest risk.
India has increasingly adopted heat action plans in cities and states over the past decade. What lessons have we learned from these efforts? Which interventions have been shown to work, and where do the biggest gaps remain?
India now has numerous Heat Action Plans (HAPs), which include early-warning systems, cooling centres, public-awareness drives, and adjusted hours for outdoor work and schools. This approach works and is inexpensive. An evaluation of Ahmedabad’s HAP, piloted in 2013, estimated an avoided 1000+ deaths a year.
Newer tools such as parametric heat insurance are emerging as well. SEWA’s parametric insurance product for women in the workforce compensates for some of the lost wages when the temperature exceeds a certain threshold for three consecutive days. This program covers 50,000 women across 22 districts in the country.
The biggest gap is implementation. Manual labourers cannot afford to stop working when heat alerts are sent. Thus, alerts that connect with an on-ground mandatory action are imperative. Reducing heat mortality could also include curbing short-lived climate pollutants like black carbon that heat the planet thousands of times more than carbon dioxide in a shorter period. Such measures would treat the underlying disease of heat stress itself, and not just its symptoms.
As climate change makes heatwaves more frequent and intense, what should India be doing differently over the next decade? Are we still treating heat as a seasonal inconvenience rather than a major public health threat?
Heat is largely treated as a seasonal nuisance and not a notified disaster under India’s disaster law, unlike floods and cyclones, which keep it outside dedicated relief funding. Treating heat as a standing public-health threat means expanding the scope and our understanding of true heat-related mortality; actively prioritising and implementing funding plans; protecting outdoor workers with rest and water; and cooling cities through shade, trees and reflective roofs.
India can also pull a faster lever: cutting short-lived climate pollutants (SLCPs). These warm the planet many times more than carbon dioxide, but last only a short time in the air. Therefore, reducing SLCPs slows warming within years, not centuries. A UNEP–WMO assessment found global action on SLCPs could avoid about 0.5°C of warming by 2050. This would mean preventing millions of heat-related mortalities. Therefore, choosing climate-friendly refrigerants and curbing black carbon offers relief that can be felt within our lifetimes.
Himanshu is a Senior Policy & Research Associate at Gateway Research. Zerin Osho is the Director of the India Program at the Institute for Governance & Sustainable Development
(IGSD)
Children at a beach in Mumbai. (Express photo by Ganesh Shirsekar) 
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