Delhi's pollution level began to rise again Wednesday as the impact of rain subsided, but the air quality index was still recorded in the 'moderate' category, authorities said.
Delhi's air drastically improved after heavy rains lashed the city Tuesday and was recorded in the 'satisfactory' category this year for the first time since October last year.
As the impact of rain subsided, the pollution level again began to rise and is expected to oscillate between 'moderate' and 'poor' category for the next three days, authorities said.
An AQI between 100 and 200 comes under the 'moderate' category, 201 and 300 is considered 'poor', 301 and 400 'very poor', while that between 401 and 500 is 'severe'.
On Wednesday, two areas recorded satisfactory air quality, while 32 areas recorded moderate air quality, the CPCB said.
In the National Capital Region, Noida, Faridabad, Ghaziabad, Gurgaon and Greater Noida recorded 'moderate' air quality, it said.
The overall PM2.5 level -- fine particulate matters in the air with a diameter of less than 2.5 micrometers -- in Delhi was 93, while the PM10 level was 139, it said.