Fog, smog, and suffering: From Delhi to Assam, cities engulfed in toxic air - see pics

A layer of smog engulfs the area around Central Delhi's Rail Bhawan as air quality remains in the 'Very Poor' category in several areas, according to the Central Pollution Control Board (CPCB).

A thick layer of smog covers the area around Akshardham as Delhi's air quality continues to remain in the 'Very Poor' category.

Dense smog covers Delhi's Kartavya Path like a blanket.

The area around north Delhi's Azadpur Mandi remains covered in a blanket of smog in the mornings, according to the Central Pollution Control Board (CPCB).

Ghazipur landfill disappears in thick smog, very poor visibility on NH9 in Delhi today.

A thick layer of smog hangs over Gurugram as the air quality continues to worsen.

A blanket of smog covers several parts of Assam's Nagaon district.

Mumbai's air quality dips to 'poor' levels as thick smog blankets several areas.

A thick layer of smog has enveloped Chandigarh, Panchkula, and Mohali, marking the season's worst air quality to date.