Recent PM_2.5 air quality improvements in India benefited from meteorological variation

Improving air quality amid rapid industrialization and population growth is a huge challenge for India. To tackle this challenge, the Indian government implemented the National Clean Air Programme (NCAP) to reduce ambient concentrations of particulate matter with diameters less than 2.5 μm (PM_2.5) and 10 μm (PM₁₀) in hundreds of non-attainment cities that failed to meet the national ambient air quality standards. Here we evaluate the efficacy of the NCAP using data from the national air quality monitoring network combined with regional model simulations. Our results show an 8.8% yr⁻¹ decrease in annual PM_2.5 pollution in the six non-attainment cities with continuous air pollution monitoring since 2017. Four of these six cities achieved over 20% reductions in PM_2.5 pollution by 2022 relative to 2017, thereby meeting the NCAP target. However, we find that ∼30% of the annual PM_2.5 air quality improvements, and approximately half of the reductions during the heavily polluted winter months, can be attributed to favourable meteorological conditions that are unlikely to persist as the climate warms. Meanwhile, in 2022, annual PM_2.5 levels in 44 out of 57 non-attainment cities with continuous monitors still failed to meet air quality standards. This work highlights the need for substantial additional mitigation measures beyond current NCAP policies to improve air quality in India.