“There is anxiety because of this heat. We can’t even think about cooking food and eating food… We can’t go out too. If we stay inside our home, we feel irritated and frustrated,” a 20-year-old woman living in a peri-urban settlement in Chennai told researchers from our foundation, as they studied the impact of heat on women’s health.
These aren’t passing complaints about a few difficult summer days. The heat is not merely oppressive, it dictates every aspect of her life — appetite, sleep, mood, movement, and small daily decisions that shape a life. For many like her, being outside is unthinkable and staying indoors unbearable, signalling that climate change now disrupts mental health, not just daily comfort.
The latest Lancet Countdown on Health and Climate Change describes a world where health consequences are no longer creeping up; they are breaking records. The report warns that health risks and impacts are now “worse than ever before” across 13 of 20 indicators — a signal that multiple climate-linked hazards are escalating at once. It also estimates there has been a 23 per cent rise in heat-related mortality since the 1990s, reaching 5,46,000 deaths a year globally.
Climate change harms health directly, through shocks including heatwaves, droughts, floods and cyclones that cause acute illness and dehydration, injuries and displacement, unsafe water, disrupted healthcare, and sudden income loss. The indirect impact, though, accumulates over time as climate stress undermines food and nutrition security, shifts geographies where disease-carrying vectors (like mosquitoes) can survive, and worsens mental health through chronic stress, livelihood threats, migration and instability
This widespread vulnerability is felt more by women, children and the poor in low- and middle-income countries, as they are severely affected due to higher exposures, greater burden of pre-existing disease, and a limited capacity to adapt.
India is making meaningful progress on mitigation. But adaptation will be the real test of health protection, because extensive exposure is already happening. The response must be multi-sectoral, starting with the most vulnerable.
One immediate safeguard is parametric insurance for gig workers, street vendors, small farmers and daily-wage workers, for whom staying home during extreme heat is not “self-care” but lost income. A payout, triggered by temperature/heat index or an officially declared climatic hazard event, can put cash in hand for a few days off. This functions as a health intervention — reducing exposure when risk spikes.
India also needs to design cooler cities as it urbanises. Update building codes for appropriate materials, ventilation and passive cooling, and scaling up nature-based solutions such as shade trees, parks, restored lakes, permeable surfaces, and blue–green corridors with priority for informal settlements where heat risk is highest and relief options are lowest. There is immense scope for innovations and catalytic funding from philanthropy to develop and test affordable cooling solutions.
The health system must be readied for climate-linked illness — especially heat stress, which is treatable only if caught early. That requires training frontline staff — including doctors, nurses, ASHAs, ANMs and Anganwadi workers — to recognise heat stress, dehydration and heat exhaustion, triage fast, and refer early. Facilities need clear cooling protocols and capacity to lower body temperature immediately, alongside routine surveillance to track heat illness, respiratory flare-ups, vector spikes and post-flood diarrhoeal disease.
Clean air is central to climate- and health-planning, not an add-on. Cutting pollution through cleaner transport, cleaner energy and stronger industrial controls delivers immediate health gains and reduces the compounded “double hit” of extreme heat-plus-poor air quality.
Soumya Swaminathan, Chairperson, MS Swaminathan Research Foundation (MSSRF), and former chief scientist at the World Health Organization
(The writer is Chairperson, MS Swaminathan Research Foundation, and former chief scientist at the World Health Organization. Views are personal)
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Published on January 12, 2026