After a day's respite, fog disrupted operations at New Delhi's Indira Gandhi International airport on Tuesday morning. 15 flights, both of domestic and international carriers, were delayed and 10 others cancelled.
General visibility dropped to 50 metres and runway visibility dipped to 150 metres, airport officials said.
A blanket of fog began to envelope the national capital's airport late on Monday night and visibility deteriorated following which airport authorities implemented low visibility procedure.
Over 100 flights were cancelled and more than 600 delayed due to dense fog last week.
As many as 40 Delhi-bound trains were running several hours behind schedule as dense fog continued to affect rail services for the ninth consecutive day.
Several morning trains from New Delhi station were also rescheduled due to the poor visibility, Northern Railway sources said.
Among the late running trains are Puri-New Delhi Purshottam Express, Rajendra Nagar (Patna)-New Delhi Rajshani Express, Howrah-New Delhi Rajdhani Express and Kashi Viswanath Express.
The Delhi-Hatia Swarna Jayanti Express has been cancelled from Tuesday till the end of the month, taking the total number of cancellations for the period up to 14.