A Tale of Five Cities: Heat Waves, Cold Spells and Mortality Risk in Urban India

Hyderabad, Mumbai and Shimla spanning 2005 - 2012. We developed Poisson regression models to study ‘the main temperature effect’ as well as ‘additional impacts’ of sustained high and low temperatures (i.e. heat and cold waves) on all-cause mortality risk. Results: We find large heterogeneity among mortality risks across urban areas. Typically, risks increase with intensity of heat (cold) waves. Populations in hotter environments may be more susceptible to cold related impacts and vice-versa. Across urban areas the main temperature effect captures most of the mortality risk. We find that ‘additional impacts’ due to sustained temperatures (heat and cold waves) is not significant. Conclusions: This is one of the first multi-city studies to examine mortality risk due to heat and cold waves in Indian cities that are spread across climatic regions and topographies. Our findings highlight the need for developing planned adaptation measures in Indian cities to minimize health impacts.