Delhi's air quality had dipped to 'very poor' category due to rains, which increased the pollutant holding capacity of air. An AQI between 0 and 50 is considered 'good', 51 and 100 'satisfactory', 101 and 200 'moderate', 201 and 300 'poor', 301 and 400 'very poor', and between 401 and 500 'severe'.
The CPCB said 16 areas recorded 'very poor' air quality while 18 areas recorded 'poor' air quality. The level of PM2.5 (particles in the air with a diameter of less than 2.5 micrometres) was recorded at 145 and the PM10 level 227, it said.
In the National Capital Region, Ghaziabad and Greater Noida recorded 'very poor' air quality while Gurgaon and Noida, recorded 'poor' air quality, the CPCB data showed. Authorities said the slight improvement in air quality is due to minor improvement in wind speed. They further added that the air quality would continue to oscillate between 'poor' and 'very poor' category for the next three days.