Additionally, the researchers discovered that 1.1 billion people, or roughly 82% of India's population, resided in regions where annual average PM2.5 levels were higher than those advised by the Indian National Ambient Air Quality Standards (40 microns per cubic meter).
Particles smaller than 2.5 millimetres in diameter are the source of fine particulate matter, or PM2.5, pollution. The researchers discovered that an annual rise in PM2.5 pollution of 10 microns per cubic metre was linked to an 8.6% increase in annual death.