Heatwaves Could Trigger 30,000 Excess Deaths in India in Just Five Days: Study

The research, carried out by Piyush Narang and Ashok Gadgil of the India Energy and Climate Center at the University of California Berkeley, sought to address the lack of accessible district-level data on heatwave-related mortality in India. The findings were published in the journal Frontiers in Environmental Health.

To estimate the nationwide impact of extreme heat, the researchers adapted findings from a multi-city study examining heat-related deaths across 10 Indian cities and applied the results to districts across the country. The study combined district-level mortality data from the Civil Registration System with 2024 population projections to calculate deaths linked to one-day and five-day heatwave events.

The researchers defined excess deaths as fatalities occurring above the number normally expected based on historical trends.

“We estimate that a single day of extreme heat causes approximately 3,400 excess deaths nationally; a five-day heatwave causes nearly 30,000,” the authors stated in the study.

The report comes as heatwave to severe heatwave conditions continue to affect northern, central and eastern India. Temperatures have remained above 45 degrees Celsius in several parts of Madhya Pradesh, Rajasthan, Uttar Pradesh and Haryana in recent days, intensifying concerns over public health and climate resilience.

According to the analysis, Uttar Pradesh alone could account for nearly 8,100 excess deaths during a five-day heatwave. Districts including Ahmedabad, Jaipur and Surat were projected to record more than 250 excess deaths each during a single heatwave event.

The study also highlighted a sharp imbalance between mortality burden and economic capacity. Uttar Pradesh, Bihar, Madhya Pradesh, Rajasthan and Gujarat together accounted for 66 per cent of the country’s projected excess deaths during a five-day heatwave despite contributing only 29 per cent of India’s Gross Domestic Product.

The researchers said the findings carry major implications for India’s heat adaptation and resilience planning. They argued that federal adaptation investment, including funding under the National Disaster Management Authority and the National Action Plan on Climate Change, should be directed toward high-burden and low-income states rather than distributed solely on the basis of population size or administrative capacity.

“The 2.3 times Gross Domestic Product disproportion documented here provides a quantitative basis for arguing that federal adaptation investment should be weighted toward high-burden, low-Gross Domestic Product states,” the researchers wrote.

The study further revealed that the 100 most vulnerable districts, home to nearly one-third of India’s population, accounted for 44 per cent of projected excess deaths during a five-day heatwave.

Researchers warned that heatwave mortality risk in India is not simply linked to population size but is structurally concentrated in states with lower economic output and limited fiscal capacity to invest in climate adaptation measures.

They added that the district-level estimates align with a growing body of epidemiological and modelling evidence indicating that South Asia, particularly India, faces rising vulnerability to heat-related deaths as extreme weather events intensify.

The findings underscore the mounting human cost of climate-driven heatwaves in India and raise urgent questions over the country’s preparedness to protect vulnerable populations from increasingly severe and prolonged periods of extreme heat.