Delhi has not recorded even a single “good” air quality day with an AQI of 50 or less in the first six months this year, according to government data presented in Rajya Sabha on Thursday.
Union Minister of State for Environment Ashwini Kumar Choubey, however, said Delhi saw a 27% reduction in PM10 and a 22% reduction in PM 2.5 in 2021 compared to 2016.
According to the data presented by the minister, Delhi has not recorded a single "good" air quality day in the first six months of this year. It has, however, logged seven "satisfactory" and 47 "moderate" air quality days during this period.
The city saw 105 "poor", 21 "very poor" and one severe air quality day, the data showed. Air quality index (AQI) between zero and 50 is considered 'good', 51 and 100 'satisfactory', 101 and 200 'moderate', 201 and 300 'poor', 301 and 400 'very poor', and 401 and 500 'severe'.
The data also showed that Chennai, Hyderabad and Bengaluru did not record even one bad (poor, very poor or severe) air quality day.
The main sources of pollution in Delhi-NCR and adjoining areas include stubble burning, especially in north-western states, open municipal solid waste burning, road dust, industrial pollution, thermal power plants, vehicular pollution and dust from construction and demolition activities, Mr. Choubey said.
During post-monsoon and winter months, low temperatures and low mixing height, inversion conditions and stagnant winds lead to the trapping of the pollutants resulting in high pollution in the region, he said.