An Air India flight bound for Vancouver was forced to turn back to Delhi after being airborne for over seven hours due to an aircraft approval issue, with sources attributing the disruption to a lapse in operational requirements for Canada-bound services.

The flight, operated on a Boeing 777-200 LR (VT-AEI), took off from Delhi on Thursday but reversed course while flying over Chinese airspace, according to data from Flightradar24.com. Sources said the aircraft used for the service was not approved for operating flights to Canada, leading to the mid-air return.

An apparent lapse in updating the list of requirements for operating flights to Canada resulted in the deployment of the wrong aircraft, sources added. They noted that the service was required to be operated using a Boeing 777-300 ER, for which approvals were in place.

Without disclosing specific details, Air India confirmed the safe return of the aircraft.

"Air India flight AI185, operating from Delhi to Vancouver on 19 March, returned to Delhi due to an operational issue and in line with established standard operating procedures. The aircraft landed safely, and all passengers and crew had disembarked," the airline said in a statement.

There are multiple regulatory approvals required for international flight operations, which vary depending on the destination country.

Air India said the affected passengers were accommodated on a rescheduled flight, which departed for Vancouver on Friday morning.