New Delhi, Jan 13 (IANS): A blanket of thick fog engulfed the national capital Tuesday morning, affecting the movement of trains and vehicles as the visibility dropped to 50 metres at 8.30 a.m.

According to an official of the Northern Railway, around 40 trains coming to the city were delayed while the departure time of four trains was rescheduled. Another eight trains were cancelled.

The fog also affected traffic as vehicles were brought to a crawl and snarls were reported from some of the major intersections of the city.

Though the Met Office has forecast a clear afternoon with partly cloudy sky, fog is likely to return in the evening.

"The afternoon will be clear and the sky will remain partly cloudy. Fog is likely to return in the evening," said an official of the India Meteorological department.

The maximum temperature is likely to hover around 16 degrees Celsius.

Tuesday's minimum temperature settled four notches below the season's average at 4 degrees Celsius, while the humidity at 8.30 a.m. was 100 percent.

Monday's maximum temperature was 16.2 degrees Celsius, five notches below the season's average while the minimum settled at 5.7 degrees Celsius, two notches below the season's average.