A thick blanket of fog descended on the national capital this morning disrupting flight operations at the Indira Gandhi International Airport. According to airport officials, several flights were delayed while three diverted.After experiencing comparatively warmer days, the chill has once again set in the capital after heavy rains lashed several parts of the city on Sunday. The maximum temperature yesterday settled three notches below average at 22.6 degrees. At 10.3 degrees, the minimum this morning was also a notch below normal.Met department predicts the sky to remain partly cloudy today with the mercury likely to oscillate between 24 and nine degrees.