Intensified Heat Stress Risks at Indian Mass Gathering Sites Due to Climate Change

Mass gatherings in India, encompassing religious and cultural events, draw millions of participants annually and are increasingly vulnerable to the impacts of climate change, particularly intensifying heat stress during summer months. This study evaluates the projected risks of heat stress at six prominent locations: Ajmer, Amritsar, Delhi, Haridwar, Prayagraj, and Ujjain. Wet-bulb temperature (Tw), a reliable indicator of heat stress, is used to assess the impacts of rising temperature and humidity levels. Simulations from dynamically downscaled bias-corrected Coupled Model Intercomparison Project Phase 6 (CMIP6) datasets, under SSP2-4.5 and SSP5-8.5 scenarios, are used from to capture the spatiotemporal variability of heat stress throughout the 21st century. Results indicate a substantial increase in maximum Tw during the summer months (March to June) across all sites. By mid-century, Tw is projected to reach or exceed “danger” levels, with Prayagraj and Delhi identified as high-risk zones. Extreme danger thresholds are anticipated at these locations by the late 21st century under the SSP5-8.5 scenario. Haridwar, while showing the lowest risk among the study sites, is not immune to the impacts of heat stress. Focusing on the intersection of climate change and public health in densely populated regions, the findings highlight the urgent need for adaptation and mitigation strategies to protect public health during future mass gatherings in India.