Dense fog hit airline operations hard on Wednesday with virtually no departures for eight hours thanks to zero visibility.
More than 200 flights were delayed by four to six hours throughout the day, while 17 were cancelled and four had to be diverted to Jaipur, Ahmedabad and Indore.
General visibility at the airport remained at zero between 1.40am and 9.40am and the runway visibility remained below the prescribed minima for low visibility take-off of 125 and 150 metres for different types of aircrafts.
Many flight, however, managed to land using the CAT III Instrument Landing System.
The Met department has forecasted similar foggy conditions on Thursday between 4am and 9am, even though passengers might receive 'slight respite'.
On Wednesday, many passengers were delayed for their scheduled meetings while some missed their connecting trains.
Kartar Singh got late for a meeting by almost two hours as his Air India flight from Lucknow was delayed.
Trains services were also severely hit. More than 150 trains ran behind schedule. All Delhi-bound Rajdhani and Shatabdis were delayed. The average delay time in arrival and departure was around eight hours.