Delhi battled toxic fumes on Sunday as the air quality slipped into the 'severe category with a reading of 459, according to the Central Pollution Control Board.
A thick layer of smog blanketed the city overnight, leaving people gasping for air.
As per the CPCB, an Air Quality Index (AQI) between zero and 50 is considered 'good', 51 to 100 'satisfactory', 101 to 200 'moderate', 201 to 300 'poor', 301 to 400 'very poor' and 401 to 500 'severe'.
On the weather front, the minimum temperature settled at 8.2 degrees Celsius, 0.4 notch below the season's average, and the maximum temperature is likely to hover around 24 degrees Celsius.
The relative humidity was 100 per cent at 8.30 am, the IMD said.
In light of the deteriorating air quality in the national capital, the Delhi Directorate of Education on Saturday directed all schools to conduct classes for students up to Class IX and XI in a hybrid mode
The Commission for Air Quality Management (CAQM) has invoked Stage-IV actions under the Graded Response Action Plan (GRAP) with immediate effect to curb further worsening of air pollution levels in Delhi-NCR.