Air pollution imposes substantial health and economic costs on India, contributing significantly to disease burden measured in disability-adjusted life years (DALYs) and to productivity losses from premature mortality and illness. Evidence synthesised by The Lancet shows that India’s air pollution burden is among the most severe globally and driven by fine particulate matter (PM2.5) and combustion-related gases. While PM10 remains relevant in dust-prone and construction-intensive urban areas, PM2.5 is more harmful due to its ability to penetrate deep into the lungs and bloodstream, contributing disproportionately to premature mortality and chronic disease. This distinction has direct implications for the design of India’s clean air policy under the National Clean Air Programme (NCAP), which remains largely PM10-centric.

PM2.5 arises both from direct emissions and from secondary formation through precursor gases such as NOx and SO2, largely emitted by transport, power and industry. Residential solid fuels, coal-based industry, waste burning and construction dust together account for the bulk of India’s pollution load. India’s national annual average PM2.5 in 2023–24 averaged 50 µg/m³ – nearly 10 times the WHO guideline with the highest concentration across the Indo-Gangetic Plain and major industrial clusters particularly during winter.