An estimated 500 domestic flights could be cancelled and as many international flights will be rescheduled due to the restrictions, an airport official said, adding it was being done due to increased traffic and capacity constraints this year.
The airspace over Delhi remains shut for commercial flights due to rehearsals in the days leading to the Republic Day on January 26.
The Airport Authority of India (AAI) has issued a NOTAM or Notice to Airmen informing the airlines that no take-offs or landings would be allowed from or to Delhi airport from 10.35 am to 12.15 pm for nine days between January 18-26, according to airport sources.
IGI witnesses 67 air traffic movement (both take offs and landings) per hour between 8 am to 11 pm every day. With airspace shut for 100 minutes for nine days, an estimated 1,000 flights will either be cancelled or rescheduled.
"On an average 100 flights will be affected every day. We will accommodate 40 international flights before or after the closure hours. Out of the remaining 60, we will try to reschedule some of the flights. So, we could see roughly 50 flights being cancelled each day," said an airport official.
The Delhi International Airport Limited, which operates IGI, says no international flights will be cancelled.
Airport officials say that while on earlier occasions they were able to reschedule most of the affected flights, severe capacity constraints at IGI mean that it can't be done anymore.
"Since we had spare capacity we were able to accommodate flights either before or after the closure hours. But because we don't have any spare capacity now, these flights have to be cancelled," said a source.
Also, the airspace closure has been extended by two days. As a result the restrictions are in place for nine days instead of seven days.
The airlines were asked to curtail operations for Republic Day on December 29, when the NOTAM was issued.
Get Breaking news, live coverage, and Latest News from India and around the world on NDTV.com. Catch all the Live TV action on NDTV 24x7 and NDTV India. Like us on Facebook or follow us on Twitter and Instagram for latest news and live news updates.