A day of extreme heat is associated with an estimated 3,400 excess deaths across India, while a heatwave lasting five consecutive days could lead to nearly 30,000 additional deaths, according to a new study.To estimate the impact nationwide, the researchers adapted findings from a multi-city study of heat-related deaths across 10 Indian cities and applied them to districts across the country. (PTI)The research, conducted 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, according to news agency PTI.Also Read | ‘Extreme heat in India, a result of worsening climate change’Multi-city finding of heat-related deathsTo estimate the impact nationwide, the researchers adapted findings from a multi-city study of heat-related deaths across 10 Indian cities and applied them to districts across the country.Excess deaths refer to the number of deaths occurring above what would normally be expected based on historical trends.Published in the journal Frontiers in Environmental Health, the study combined district-level mortality data from the Civil Registration System with 2024 population projections to estimate deaths linked to one-day and five-day heatwave events.Also Read | Brutal June, above-normal heat wave days, rain forecast cut further: Key IMD projections3,400 deaths nationally, 30,000 in five-days"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 wrote.The findings come as heatwave to severe heatwave conditions continue across northern, central and eastern India.Temperatures have remained above 45 degrees Celsius in parts of Madhya Pradesh, Rajasthan, Uttar Pradesh and Haryana in recent days.What areas were impacted most?The analysis found that Uttar Pradesh alone could account for around 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.Researchers also identified a significant mismatch 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 GDP.The researchers said the findings have important implications for India's heat adaptation and resilience planning."The 2.3× GDP disproportion documented here provides a quantitative basis for arguing that federal adaptation investment, including funding under the National Disaster Management Authority and the National Action Plan on Climate Change, should be weighted toward high-burden, low-GDP states rather than allocated in proportion to population or administrative capacity," they wrote.100 most vulnerable districtsThe study also found 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.Further, "heatwave mortality risk is not merely proportional to population size but is structurally concentrated in states with lower economic output (which are) precisely those with the least fiscal capacity to invest in adaptation," the authors said.They added that the district-level estimates are consistent with a growing body of epidemiological and modelling evidence indicating that South Asia, particularly India, faces heightened vulnerability to heat-related deaths.(With PTI inputs)