Interstate migration enhanced ambient PM_2.5 attributable health burden in India

Abstract Interstate migration, shaped by socioeconomic and demographic drivers, substantially modifies population dynamics across states relative to the ‘ no-migration ’ condition. However, the impacts of migration on ambient PM 2.5 -attributable premature deaths and disability-adjusted life years (DALYs) have not been quantified in India. Using the global burden of disease framework, we integrated census-based population estimates with satellite-derived ambient PM 2.5 concentrations at a 1 × 1 km 2 resolution to estimate air pollution-attributable premature deaths and DALYs in 2011. While the migration statistics from 2001–2011 was used to assess the changes in health burdens due to interstate migration compared to a ‘ no-migration ’ scenario. We then isolated the effects of migration-driven changes in population dynamics and air pollution exposure on the migration-related changes in health burdens. And finally, we apportioned these burdens across five major socio-demographic drivers of migration: employment, education, household movement, marriage, and other reasons. Interstate migration was estimated to increase PM 2.5 -attributable premature deaths by 8483 (95% UI: 7211–9755) and DALYs by 234 662 (192 423–276 901). Outward migration from underdeveloped states such as Uttar Pradesh, Bihar, and Rajasthan reduced their local air pollution-related health burdens, whereas wealthier states including Maharashtra, Delhi, and Haryana absorbed the excess burden. Migration-induced changes in population dynamics and air pollution exposure exerted unidirectional effects on health burdens, with demographic shifts having a stronger influence than changes in exposure across the states. Among the socio-demographic drivers, marriage and employment accounted for 52% and 32% of the excess migration-induced health burdens, respectively, while other factors contributed less and varied regionally. Given that interstate migration is projected to rise under future climate change, these findings suggest that disparities in air pollution-related health burdens will likely intensify across India.