A thick blanket of fog covered Delhi and the NCR region on Monday due  to the sharp decline in temperature with the winter chill tightening its grip.

Visibility was reduced to a few metres in the morning hours and vehicles were being driven with their headlights on. The air quality was in the ‘very poor’ category with an overall AQI of 327 in Delhi today.

The minimum temperature has plunged to 7 degrees in the national capital. while the maximum as hovering at around 23 degrees. The temperature is expected to come down further this week.

The AQI in Noida was recorded at 399 while AQI in Gurugram stood at 302.

The Air Quality Index from 0 to 100 is considered as good, while from 100 to 200 it is moderate, from 200 to 300 it is poor, and from 300 to 400 it is said to be very poor and from 400 to 500 or above is considered as severe.

The Air Quality of the national capital, which was at a moderate level for the last few days, dipped over the weekend.

According to the System of Air Quality and Weather Forecasting and Research (SAFAR), Delhi’s air quality was also recorded in the ‘very poor’ category on Sunday.