Authorities at the Delhi airport on Friday searched a Vistara aircraft, which was to leave for Pune, following a bomb threat but nothing suspicious was found, the police said.
In a statement, Vistara said flight UK971 had been delayed due to "mandatory security checks".
A senior Delhi police officer said a threat call received at the Delhi International Airport Limited (DIAL) control room in Gurugram was transferred to them through the Central Industrial Security Force (CISF).
Following the call, search and combing operations were launched.
"The passengers were deboarded and we checked the aircraft from inside and outside but nothing suspicious was found. A case is being registered and further investigation is underway," the officer said.
Flight UK971 was to depart at 8:30 am, according to the police.
Airport security sources said the airport call centre received a call at 7:38 am and the caller said that "three bombs have been kept in flight no. UK971 parked at gate no. 42 and they will explode in an hour". The call got disconnected immediately.
All passengers and crew of the flight were deboarded and anti-sabotage checks were conducted in an isolation bay at the Indira Gandhi International (IGI) Airport, they said.
A bomb threat assessment committee (BTAC) was convened soon after and bomb detection equipment and sniffer dogs were pressed into service by the CISF while passengers' luggage was sent for a re-check, they added.
In its statement, Vistara said it is cooperating with the security agencies.
"We confirm that the flight UK971, scheduled to fly from Delhi to Pune on August 18, 2023, is delayed due to mandatory security checks," it said.
"In the meanwhile, we are making all efforts to minimize inconvenience to our customers including offering them refreshments," it said.