Officials said an area with a radius of 300 km around IGI will be a no-fly zone. The Directorate General of Civil aviation (DGCA) issued the guidelines to all airlines and the air traffic controller on Saturday evening. Flights scheduled during this one hour have been asked to reschedule. “All unscheduled flights to and from Delhi have to maintain a radius distance of 300 km from the airport. All flights passing over Delhi are supposed to maintain a height of 1,200 feet,” a senior airport official said.

Officials said this step has been taken keeping in mind the several terror threats pertaining to an attack on the Capital. Heavy security arrangements have been made at the airport by the CISF and Delhi Police, apart from arrangements made by DIAL.

Northern Railways has also made special security arrangements in coordination with the state police, local intelligence agencies, and the Railway protection Force (RPF).

Additional staff has been deployed for anti-sabotage checks in railway installations, passenger coaches, and railway infrastructure. The staff has been advised to remain vigilant, and keep a look out for suspected individuals boarding or deboarding at stations en route. Sniffer dogs too have been deployed to assist in the anti-sabotage checks.

On any given day, the Railways deploy 172 Railway Police officials to guard the New Delhi Railway Station. On days such as the Republic Day, 90 more RPF personnel are deployed and 10 per cent of all guards at the station are armed.

In addition, 35 CCTV cameras will monitor the traffic at the station on Monday. “We have also provided additional hand-held metal detectors and each entry and exit point at the station will be strictly monitored. RPF personnel will monitor the bridges and even the tracks and passengers will have to submit to enhanced frisking,” A S Negi, Northern Railways public relations officer, said.