A thick blanket of smog is covering Delhi and Mumbai, as the air quality dipped further amid cold wave conditions.

The Air Quality Index (AQI) in the national capital stood at 386 in the 'very poor' category for the second consecutive day on Sunday morning, media reports said.

In Mumbai, the AQI was 176 in the 'moderate' category.

An AQI between 0 and 50 marks as good, 51 and 100 satisfactory, 101 and 200 moderate while a record between 201 and 300 is poor, 301 and 400 very poor, 401 and 450 severe, and above 450 severe-plus.

Delhi AQI:

With Delhi's air quality deteriorating again, the Commission for Air Quality Management (CAQM) has imposed GRAP 4 restrictions in the national capital and its adjoining areas from Monday night.

The Air Quality Index reached the 400 mark, and dipped into the 'Severe' category on Monday.

The AQI on Saturday stood at 370 in the 'very poor' category, with the visibility dropping in the national capital. The Delhi Airport also issued an advisory for passengers saying, "Low visibility procedures are in progress at Delhi Airport. All flight operations are presently normal. Passengers are requested to contact the airline concerned for updated flight information."

Under GRAP-4 restrictions, all schools are shifted online and a ban is imposed on Delhi-registered BS-IV or older diesel medium and heavy goods vehicles. All the construction activities in the national capital are also halted.

On Saturday, the AQI on Saturday stood at 370 in the 'very poor' category, with the visibility dropping in the national capital.

The Delhi Airport also issued an advisory for passengers saying, "Low visibility procedures are in progress at Delhi Airport. All flight operations are presently normal. Passengers are requested to contact the airline concerned for updated flight information."

Mumbai Air Quality:

This year, Mumbai has been witnessing its coldest winters in decades, bringing its air quality down.

For the fourth consecutive day, the city was covered in a blanket of smog with the overall AQI touching 176.

Earlier this week, the AQI also touched 199 in the 'poor' category.

Several citizens posted videos and pictures on social media showing the worsening air quality in Mumbai.