According to Met department, runway visibility at the IGI Airport was reduced to less than 125 metres, disrupting flight schedules of international and domestic carriers.
Airport officials said that nine international arrivals and four departures have been delayed due to poor visibility.
At the domestic wing of the IGI Airport, four arrivals were delayed and 12 departures have been cancelled.
The dense fog also hit rail traffic as well, with over 100 trains getting delayed and 10 cancelled. Seventeen other trains have been rescheduled.
The situation was no better on roads, with visibility reducing to as low as few metres in several parts of Delhi and NCR towns.