The visibility in the morning was 800 metres in most parts of the city, he said.
However, the visibility in Palam area was 350 meters.
According to the System of Air Quality and Weather Forecasting And Research (SAFAR), the overall air quality in the national capital was found in 'very poor' category.
"While there was shallow to moderate fog in most parts of the city, a few places saw dense fog causing visibility issues. The sky will remain clear with cold wave conditions at some isolated places," the official said.
There would be haze and smog later in the day.
Thursday's maximum temperature settled at 22 degrees Celsius, a notch above the season's average, while the minimum temperature was recorded at 3.7 degrees Celsius, four notches below the season's average.