If you are travelling out of Delhi starting January 18, recheck your flight bookings. Starting the said date, the airspace over Delhi will be closed for 60-90 minutes for Republic Day rehearsals of the air show that has become a constant feature over the years. In the past, flights would just be rescheduled, but thanks to congestion this year, the airlines have decided to cancel them altogether during that time frame. According to a notice, the airspace over Delhi will be closed from 10.30 am to 12.15 pm between January 18-26, 2018. While the cancellations only apply to domestic flights and affect over 15,000 passengers, international operations will continue.