After remaining under the "very poor" category, the Air Quality Index (AQI) in Delhi reached 221 on Tuesday under the "poor" category, according to data from the System of Air Quality and Weather Forecasting And Research (SAFAR).

While Dhirpur recorded an AQI of 303 under the "very poor" category, at Lodhi Road the AQI with PM 2.5 concentration was at 197 and the PM 10 stood at 148 both under the "moderate" category.

Meanwhile, the PM 2.5 was at 218 under the "poor" category at the IIT Delhi station, while the PM 10 reached 165 in the "moderate" category.

Mathura Road was under "moderate" category with PM 2.5 at 163 with PM 10 concentration at 128.

In Pusa, it was 145 falling under "moderate" category.

The 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".