In April 2018, the Ministry of Environment, Forest and Climate Change (MoEFCC) launched a draft plan for National Clean Air Programme (NCAP). NCAP aim at a long term, time-bound, city-level strategy to reduce 20% to 30% of PM concentration by 2024 keeping 2017 as the base year for the comparison of concentration.
Initially, 102 cities were listed as non-attainment cities under NCAP which later was updated to 122 non-attainment cities in 2019. Based on the 2008-2010 National Air Quality Monitoring Programme data, cities that have violated the prescribed National Ambient Air Quality Standards (NAAQS) were identified as Non-attainment cities by the CPCB.
Despite having all polluting sources and being one of the largest industrialised cities in the country, Chennai is not included in the list of non-attainment cities listed.