Airport sources said that the two flights were halted after the Jet Airways security office at Indira Gandhi International Airport here received an anonymous call saying there was a "bomb threat" to Air India flight AI-215 and Jet Airways flight 9W 260.
The two flights were scheduled to take off for the Nepalese capital at 0115 hour and 0130 hours, respectively.
This is the second such incident of grounding of an aircraft due to a bomb scare as on Saturday the same flight of Jet Airways was delayed by six hours due to the grounding of the plane after a bomb threat call, which turned out to be a hoax.
The two aircraft have been taken to the isolation bay, where security personnel from Bomb Disposal Squad (BDS) are carrying out an extensive search of the baggage and check-in luggage of the passengers, the sources said.
"Jet Airways flight 9W 260, scheduled to depart from Delhi for Kathmandu at 1325 hrs, has been delayed due to a security alert. All 122 guests and 7 crew have been taken to the departures waiting area at the airport," Jet Airways said in a statement.