Rising Temperatures Could Kill 400,000 in South Asia by 2045, India at High Risk: Study

As temperatures rise relentlessly across South Asia, India stands at the heart of a crisis that could define the region’s public health future. A new study published in Environmental Health Perspectives warns that deaths linked to high temperatures in South and Southeast Asia reached over 240,000 in 2021 — and that number could double by 2045 if emissions and heat-mitigation efforts do not intensify.

The report, titled “Disease Burden Attributable to High Temperature between 1990 and 2021 in South Asia and Southeast Asia, with Projections to 2045,” estimates that 209,537 deaths in South Asia — most of them in India — were attributable to extreme heat in 2021, alongside 32,230 deaths in Southeast Asia. Researchers warn that annual heat-related deaths in South Asia could exceed 400,000 by 2045, with India bearing the brunt.

“South Asia has emerged as one of the most vulnerable regions in the world to heat-related mortality,” the report notes, citing population density, rapid urbanisation, limited access to cooling, and high baseline temperatures as key factors.

India at the epicentre

India, home to more than 1.4 billion people, has seen a steady surge in heatwave intensity and duration over the past decade. From Delhi to Rajasthan, Bihar to Telangana, temperatures now routinely exceed 45°C, pushing the limits of human endurance. Cities across northern and central India have reported spikes in hospital admissions for heat stroke, dehydration, and cardiovascular complications during the pre-monsoon months.

According to the study, the elderly, children under five, and outdoor workers are most vulnerable. “The very young and the older age groups experience a higher disease burden attributed to high temperature,” it states. Daily-wage labourers, farmers, and construction workers—many without access to shade or hydration—are among those most exposed.

The report’s findings echo the ground realities observed across India in recent summers. Heatwaves that once lasted two or three days now stretch beyond a week. Night-time temperatures remain dangerously high, offering little relief to those without air-conditioning or proper ventilation. Urban heat islands—created by concrete sprawl and loss of green cover—are making cities even more uninhabitable during peak heat months.

According to multiple bulletins issued by the India Meteorological Department (IMD), the summer of 2024 was among India’s harshest on record, with prolonged heatwave and severe heatwave conditions sweeping large parts of the country between March and June. States such as Uttar Pradesh, Odisha, Bihar, Delhi, and Rajasthan faced sustained spells of extreme temperatures exceeding 45°C. In response, several state governments closed schools, curtailed outdoor work, and issued public advisories. A national report by the National Centre for Disease Control (NCDC) under the Ministry of Health confirmed dozens of heatwave days and widespread warm-night events across 17 states and union territories during this period, underscoring the growing severity of India’s heat crisis.

Doctors and health experts have long warned that India underestimates its heat-related mortality burden. Many heat deaths are never officially classified as such. “We don’t classify and measure deaths as much as we should,” one health expert told Associated Press during India’s record-breaking summer earlier this year.

The result is a public health blind spot. “High temperatures are escalating emergency-department visits, hospitalisations, and mortality rates, with significant rises in cardiovascular and respiratory disease mortality,” the new report states. Yet, official data remain sparse, and most regions lack systematic heat-illness surveillance or hospital-level reporting.

South Asia’s shared struggle

Beyond India, the crisis extends through the subcontinent. Pakistan, Bangladesh, Nepal, and Sri Lanka all face similar vulnerabilities—crowded cities, fragile health systems, and limited adaptation capacity. For millions of people across South Asia, access to electricity, clean water, or cooling infrastructure remains inconsistent.

The study projects that South Asia’s heat-related death toll could multiply several times over by 2045, threatening not only lives but livelihoods. Agricultural productivity is expected to decline as heat stress affects both crops and farm workers. Water scarcity, migration pressures, and inequality will deepen existing social fractures.

As the authors warn, “High temperature is a growing and urgent health threat in South and Southeast Asia, requiring coordinated regional strategies and early-warning systems to prevent mass mortality events.”

A recent Asia Insurance Review analysis also noted that Asia accounts for more than half of global deaths caused by high temperatures, underscoring the disproportionate toll on the region’s poor and densely populated countries.

The global picture: heat as a universal killer

The South Asian crisis is part of a global pattern. Around the world, nearly half a million deaths were attributed to high temperatures in 2021, with Asia accounting for the largest share. Europe, North America, and Africa are also witnessing unprecedented heat-related mortality and economic losses.

The Lancet Countdown on Health and Climate Change (2024) reported that extreme heat exposure globally increased by 86% between 1986 and 2022, and labour productivity losses now exceed billions of work hours annually. Regions once unaccustomed to extreme heat—such as southern Europe and the Pacific Northwest of the United States—are also seeing deadly heatwaves.

But in poorer tropical countries, including India and its neighbours, the impacts are compounded by lack of cooling infrastructure and weak health systems. In effect, the global heat crisis is universal, but its deadliest consequences are concentrated in South Asia.

Urgency for action

The implications for India and the region are dire. Without urgent adaptation, heatwaves could become the leading cause of climate-related deaths in the next two decades. Public-health systems must prepare for a surge in heat-stroke and dehydration cases, cities must invest in green spaces and reflective surfaces, and local governments must expand access to water, shade, and early-warning systems.

Experts call for comprehensive heat-action plans, modelled on Ahmedabad’s pioneering HAP (2013-onwards), to be scaled nationwide. Urban planners are urged to integrate “cool roofs,” tree-lined streets, and ventilation corridors into city designs. At the same time, long-term emission reduction is critical: the Intergovernmental Panel on Climate Change (IPCC) warns that every fraction of a degree in warming dramatically raises the risk of lethal heat events.

“Heat is a silent killer,” the authors stress. “It’s impacts are preventable, but only if we act with urgency.”

References:

https://pmc.ncbi.nlm.nih.gov/articles/PMC12573994

https://mausam.imd.gov.in

https://ncdc.mohfw.gov.in/wp-content/uploads/2024/12/Report-of-Heat-Related-Activities-2024_NPCCHH.pdf

https://apnews.com/article/india-heatwave-deaths-heat-stroke-climate-change-880f26e3b8eeb066d2db2308502783d2

https://www.asiainsurancereview.com/News/View-NewsLetter-Article/id/93409/Type/eDaily/Asia-accounts-for-more-than-half-of-the-global-deaths-due-to-high-temperature

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(25)01919-1/abstract

https://www.ipcc.ch/ https://www.nrdc.org/sites/default/files/ahmedabad-heat-action-plan-2018.pdf

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