Kolkata has witnessed an overall improvement in PM10 concentration in the air in the last four years.
Only 95 out of 132 non-attainment cities covered under the National Clean Air Programme (NCAP) have seen improvement in air quality during this time. Earlier, these cities had failed to meet the prescribed national ambient air quality standards for five consecutive years from 2011 to 2015.
The cities with a marked improvement in air quality include Delhi, Noida, Ghaziabad, Mumbai, Kolkata, Chennai, Bengaluru, Chandigarh, Dehradun, Patna, Nagpur, Pune, Agra, Allahabad, Bareilly, Firozabad, Moradabad, Kanpur, Varanasi, Jalandhar, Ludhiana, Jaipur, Jodhpur, Jamshedpur, Ranchi and Raipur.
NCAP, launched in 2019, is a flagship programme taken by the Environment ministry to ensure better air quality in Indian cities. It targets 20 to 30 per cent reduction in particulate matter concentration by 2024.
The acceptable annual standard for PM 10 and PM2.5 is 60 micrograms per cubic metre and 40 micrograms per cubic metre respectively.