According to airport sources, not just passengers but also flight and cabin crew were stuck in massive traffic snarls.
The alarming situation led various airlines to announce waiver of cancellation charges.
"Due to heavy traffic congestion on Delhi-Gurugram Highway, customers who miss their flight due to this will be accommodated on next Vistara flight for no extra fee or fare on the basis of seat availability from Delhi," the airline tweeted.
"We are also offering free changes and cancellations for those who are booked to travel from Delhi today. Fare difference if any, will be applicable."
A GoAir spokesperson said the airline is offering "rescheduling/cancellation fee waiver to passengers travelling to/from #Delhi for today 19th Dec'19 and tomorrow 20th Dec'19 (fare difference, if any, will be applicable)".
IndiGo said that "due to the ongoing protests in certain areas of Delhi and NCR, and the restrictions on traffic into Delhi capital, especially from Gurgaon..." and "to accommodate passengers reaching late to the airport, we have rescheduled and curtailed our schedule in and out of Delhi by approx. 20 departures (approximately 10 per cent of our Delhi departures)".
Airport sources said that over 15 flights have been delayed due to traffic jam at NH-8, while a source said that IndiGo has cancelled 19 flights due to crew getting stuck in traffic jam and other issues.
( With inputs from IANS )