In pics | Delhi chokes on toxic air, thick fog reduces visibility

The air quality in Delhi continued to remain in the 'severe' category on Thursday morning, with the Air Quality Index (AQI) crossing 400 in most places.

Earlier, the India Meteorological Department (IMD) has said that shallow fog-like conditions are expected to prevail in Delhi over four days.

The AQI was 442 in Bawana, 441 in Jahangirpuri, 416 in Dwarka, 415 in Alipur, 412 in Anand Vihar, 412 in ITO, and 401 near the Delhi airport, according to data shared by the Central Pollution Control Board (CPCB).

A thick layer of smog has covered Delhi over the past few days due to a significant dip in air quality, further reducing visibility.

Delhi's overall air quality stood at 401 on Wednesday and the city's minimum temperature was recorded three notches below normal at 10.9 degrees Celsius.

Delhi was the most polluted city in the world on Tuesday, followed by Lahore and Mumbai, IQAir, a Swiss company that specialises in air quality monitoring, showed on November 14.

According to doctors, breathing in the polluted air of Delhi is equivalent to the harmful effects of smoking approximately 10 cigarettes a day, reported news agency PTI.

Delhi's air quality has dropped over the last few days despite the city government implementing stringent measures. 

Firecrackers were also burst on Diwali, despite plummeting air quality and a ban on crackers by the Supreme Court.

Toxic foam was seen floating on the surface of the river Yamuna in Delhi ahead of Chhath Puja festival.