Abstract

Heatwaves have increasingly emerged as a significant natural hazard in India, yet the absence of a comprehensive national dataset has limited our understanding of their frequency, distribution, and impact. This study aims to fill this knowledge gap by analyzing heatwave events and their associated impact across India from 1967 to 2023. Data were sourced from the Disastrous Weather Events reports published by the India Meteorological Department. The analysis examined temporal and spatial patterns, including month-wise, state-wise, and region-wise variations in heatwave events and fatalities. Key metrics—such as events, fatalities, event rate, fatality rate, event density, fatality density and fatalities per event—were assessed. A moderate positive correlation (r = 0.311, p < .001) was found between annual heatwave occurrences and fatalities. Hierarchical cluster analysis and scatter plot further revealed spatial and temporal clustering of heatwave impacts. The study also assessed secondary consequences, including illness, hospitalization, child fatality, animal deaths, crop losses, and water shortages. Additionally, the influence of El Nino and La Nina events was analyzed for the number of heatwave events and fatalities during, before, and after such events. The impact of the southwest monsoon on heatwave distribution is also discussed. Projections indicate an increase in heatwave events (n = 43) and fatalities (n = 395) by 2030. A comparative global overview confirms that heatwaves are becoming a major hazard worldwide. The findings underscore the urgent need for targeted mitigation strategies at local, national, and international levels to protect vulnerable populations and advance public health resilience in the face of climate change.

Keywords: Climate extreme, Disaster, Climate change, Heatwave, India, Meteorological hazard