The air quality of the national capital remained in the "severe" category on Saturday morning with the AQI settling at 407 at 9 am, according to the

Northern India encountered the recurring annual pre-winter event of air emergency where the Air Quality Index (AQI) readings of main pollutant PM 2.5 breached the 400-mark of “very poor” and landed the air of Delhi, Punjab and other northern cities into the “hazardous” category.

After reaching a peak, Delhi’s AQI has remained in the ‘severe’ category for the fourth day in a row. Covered in a thick blanket of fog and pollution, the poor visibility has even caused many school to remain closed for the past few days.