A dense fog enveloped Delhi and nearby regions early Saturday (16 November) as the national capital’s air quality index (AQI) remained in the ‘Severe’ category for the fourth straight day. Delhi’s overall AQI was recorded at 404 on Saturday morning, placing it in the ‘Severe’ category, according to data from the Central Pollution Control Board.

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.