Air pollution crisis: On January 10, 2019, the National Clean Air Programme (NCAP) was launched by the Ministry of Environment Forest and Climate Change (MoEF&CC) as a "time-bound, national-level strategy" to tackle the air pollution crisis in the country in a comprehensive manner. The tentative national level target of a 20-30% reduction of PM2.5 and PM10 concentration by 2024 was proposed under the NCAP, taking 2017 as the base year for the comparison of concentration. With 131 cities in focus, in 2022, the NCAP target was revised to a 40 per cent reduction in particulate matter concentration in cities and the deadline was extended till 2025-26. Four years down the line, how has the NCAP programme performed so far? Here is what experts have to say.