Question raised in Lok Sabha on Abatement of Air Pollution, 21/03/2017. The quality of air in Delhi can be assessed as per National Air Quality Index (NAQI) which classifies it into good, satisfactory, moderate, poor, very poor, and severe categories. As per AQI data for Delhi, the number of days during which air quality was satisfactory during 2015 between May and December were 23, the number of moderate days were 77, number of poor days were 73, number of very poor days were 54 and number of severe days were 8. During 2016, number of satisfactory days were 24, number of moderate days were 85, number of poor days were 120 and number of very poor days were 97. The number of severe days in 2015 and 2016 were 8 and 28, respectively. During January to March 2017, the AQI varies between moderate and very poor. The number of moderate days were 13, number of poor days 39 and number of very poor days were 24. The data relating to Air Quality Index for Delhi is annexed.