A blanket of haze enveloped the national capital on a cold day on Sunday, prompting the people to wear masks outside home.
Air quality dropped to hazardous levels in the city. The choking smog even disrupted the third Test between Sri Lanka and India.
The embattled Sri Lankan cricket team held up play, complaining of poor air quality that forced the hosts to declare their innings.
The first-ever incident of this kind in the sport's 140- year-old history saw an international team resort to anti-pollution masks while fielding and then refusing to continue.
The India Meteorological Department said pollution levels have spiked due to calm conditions, marked by low wind speed and moisture.
The IMD has forecast possibility of light rains on December 5 and 6.
Meanwhile, the city recorded a high of 23.9 degrees Celsius, a low of 8 degrees Celsius, a MeT department official said.
The humidity levels oscillated between 39 and 94 per cent.
The weatherman has predicted partly cloudy sky tomorrow (December 4).
"Mist/shallow fog likely to occur in the morning. The maximum and minimum temperature would be around 24 and 9 degrees Celsius respectively," the MeT official said.