Extreme temperature events and their relationship with excess all-cause mortality in Chandigarh, India

TL;DR

This study finds that extreme heat in Chandigarh, India, is linked to increased mortality, especially during heatwaves.

Contribution

The study identifies a critical temperature threshold of 33.8°C linked to increased mortality during heatwaves in Chandigarh.

Findings

A strong model fit (R2 = 0.996) was found between temperature and mortality.

Mortality risk increased during heatwaves with a threshold of 33.8°C.

Males and females showed similar mortality risk during heatwaves.

Abstract

Climate change has increased the frequency and intensity of extreme temperature events, adversely impacting human health and mortality. This study examines daily all-cause mortality concerning daily maximum and minimum temperature over a six-year period (2010–2015) in Chandigarh, India. Using an over-dispersed Poisson Generalized Additive Model (GAM), with visibility as a surrogate for other meteorological factors, we found a strong model fit (R2 = 0.996; P < 0.05). Our results show a significant increase in all-cause mortality during heatwave conditions. A moderately positive association between temperature and mortality was observed in summer (R2 0.014 in May; R2 = 0.133 in June; p < 0.05), while a negative association was found in winter (r = −0.155 in December; r =  − 0.141 in January; p < 0.05). A critical temperature threshold of 33.8 °C (p = 0.0007) was identified, above which mortality significantly increases, although the effect size remains modest. Mortality risk was found to be elevated during heatwaves, with similar risk levels observed for both males and females. These findings highlight the need for targeted interventions and adaptation strategies to reduce temperature-related mortality, particularly in vulnerable populations exposed to extreme weather conditions.

The online version contains supplementary material available at 10.1038/s41598-025-32614-6.

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