The visibility was 200 metres at Safdarjung, Delhi's main weather station.
Moderate to dense fog was witnessed in parts of Delhi on Saturday morning even as visibility improved in several areas, the Met office said.
The visibility was 200 metres at Safdarjung, Delhi's main weather station, and 500 metres at the Ridge, the India Meteorological Department said.
Train services were impacted due to the fog for the fourth consecutive day on Saturday with 30 Delhi-bound trains getting delayed, officials said.
Saturday's maximum temperature settled at 20.3 degrees Celsius, normal for this time of the year, while the minimum temperature was recorded at 11.8 degrees Celsius, five notches above the season's average, the IMD said.
The relative humidity oscillated between 88 per cent and 87 per cent.
According to the IMD, a layer of moderate to dense fog is likely to blanket the city on Sunday as well.
The sky will remain partly cloudy and the maximum and minimum temperatures are expected to settle around 19 and 11 degrees Celsius, it said.
An IMD advisory for Delhi, Punjab, Haryana, Uttar Pradesh, Bihar, north Rajasthan and north Madhya Pradesh said fog may affect the visibility at some airports, highways and railway routes on Sunday.
Meanwhile, the city's 24-hour air quality index was recorded at 400 at 4 pm, which falls under the "very poor" category.
An AQI between zero and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", and 401 and 500 "severe".
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