A new modelling study has estimated that extreme heat in India could be causing a far higher mortality burden than previously captured in official statistics, with researchers calculating that a single day of severe heat may lead to about 3,400 excess deaths nationwide, while a prolonged five-day heatwave could contribute to nearly 30,000 deaths. The study, conducted by researchers Piyush Narang and Ashok Gadgil from the India Energy and Climate Center at the University of California, Berkeley, uses district-level demographic and mortality data to estimate heat-related deaths across the country. The analysis is based on adapting results from earlier multi-city epidemiological studies and scaling them across India’s districts using population projections and Civil Registration System mortality patterns for 2024.

The researchers define “excess deaths” as the number of deaths occurring above the expected baseline for a given period, based on historical averages. This method is widely used in public health to estimate mortality impacts of extreme events, including pandemics and heatwaves. According to the study, heatwave and severe heatwave conditions across northern, central, and eastern India—where temperatures have recently exceeded 45°C in states such as Madhya Pradesh, Rajasthan, Uttar Pradesh, and Haryana—represent a growing and uneven public health risk. The findings suggest that mortality impacts are not evenly distributed but are heavily concentrated in specific regions with both high exposure and limited adaptive capacity.

One of the key results highlights that Uttar Pradesh alone may account for roughly 8,100 excess deaths during a five-day heatwave scenario, making it the most affected state in absolute terms. District-level modelling also shows that major urban and semi-urban centres such as Ahmedabad, Jaipur, and Surat could each experience more than 250 excess deaths in a single heatwave episode. The study also identifies a structural inequality in heat vulnerability. The five highest-burden states—Uttar Pradesh, Bihar, Madhya Pradesh, Rajasthan, and Gujarat—account for around 66% of projected heatwave-related excess deaths while contributing only about 29% of India’s GDP. This imbalance, described as a 2.3-fold disproportion between mortality burden and economic capacity, suggests that regions least able to invest in resilience infrastructure are also the most exposed to extreme heat risks.

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Researchers argue that this mismatch has direct implications for policy design. They recommend that federal adaptation funding mechanisms, including those under frameworks such as the National Disaster Management Authority and the National Action Plan on Climate Change, should prioritise high-burden, low-income states rather than relying solely on population-based allocation formulas. The study further estimates that the top 100 most affected districts—home to nearly one-third of India’s population—account for approximately 44% of all excess deaths during a five-day heatwave scenario. This indicates that heat mortality risk is geographically concentrated rather than uniformly distributed across the country.

Beyond raw numbers, the authors emphasise that heat-related mortality is closely linked to structural factors such as access to healthcare, housing quality, urban planning, labour conditions, and availability of cooling infrastructure. Outdoor workers and densely populated urban settlements are particularly vulnerable during sustained high-temperature events. The findings align with a growing body of global climate-health research suggesting that South Asia is among the regions most exposed to increasing heat stress under climate change. Scientists warn that without targeted adaptation measures—such as heat action plans, early warning systems, and urban cooling strategies—the mortality burden is likely to rise further in coming decades. Overall, the study highlights that extreme heat is not only an environmental hazard but also a significant and uneven public health crisis with deep socioeconomic dimensions.

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