A study in The Lancet Planetary Health estimated that chronic exposure to fine particulate matter (PM2.5) is associated with roughly 1.5 million excess deaths per year in India, relative to a counterfactual in which the country met the World Health Organization air quality guideline. PM2.5 penetrates deep into the respiratory system and the circulation, and is linked to cardiovascular and respiratory disease.
Drawing on nationwide data from 2009 to 2019, the analysis estimated that each 10 microgram per cubic meter increment in PM2.5 corresponded to about an 8.6% increase in mortality. Contextually, Delhi's annual mean has exceeded 100 micrograms per cubic meter, against a WHO guideline of 5 and an Indian standard of 40, underscoring the magnitude of exposure.
Interpreting the headline figure requires care. These are modelled, attributable deaths rather than individually certified ones, derived from statistical associations and explicit assumptions, so estimates vary by method. An earlier Global Burden of Disease estimate placed India nearer 1 million annually, whereas this study estimated approximately 1.5 million, illustrating the sensitivity of the total to methodological choices. As observational research, without randomised exposure, it is vulnerable to confounding by factors such as poverty, household air pollution, occupation, and healthcare access. The authors employed a difference-in-differences style design that compares variation across places and time to mitigate confounding, which strengthens causal interpretation without fully eliminating uncertainty. The robust conclusion across the literature is not a single exact number but a consistent direction and large approximate scale: PM2.5 imposes a substantial mortality burden in India.