Panic gripped 200-odd passengers onboard an SIA flight from Singapore to the IGI Airport in New Delhi today after oxygen masks automatically dropped down, forcing the pilot to make a U-turn and land back at the Changi Airport two hours after being airborne.

All the passengers are, however, safe and were flown back to their destination, Singapore Airlines said.

Technical snag seems to have caused the sudden dropping of the oxygen masks, sources said.

"It was very scary as the oxygen masks were deployed without any reason. They came down just after about two hours of being departed from Singapore. It seemed to have taken place because of some maintenance issue," Sanjay Upadyay, a passengers who was travelling to New Delhi on the snag-hit flight told PTI over phone.

Singapore Airlines confirmed the incident and said that the aircraft returned to Singapore without any incident.

"Flight SQ406, an Airbus A380, operating from Singapore to New Delhi on 29 September, returned to Singapore after oxygen masks deployed during the aircraft's climb. There was no depressurisation and initial indications are that there was a system fault," an SIA spokesperson said in an e-mail statement.

The aircraft arrived in Singapore without incident at 10:39 p.m. (Singapore time), it said, adding that following an aircraft change, the flight departed again at 0:30 a.m. hours on September 30 (Singapore time).