The flight 9W-697 with 166 passengers and five crew, was forced to return back to Mumbai shortly after take-off, said a Jet Airways spokesperson.

Several passengers complained of severe headaches and at least 30 reported bleeding from nose and ears and were immediately administered first-aid by a team of doctors at the airport.

Airline sources said that the incident may have happened after the crew reportedly missed activating what is called a 'bleed switch' before take-off, leading to the disturbance in the cabin pressure with oxygen masks getting deployed.

The Jet Airways said it has taken the concerned crew off-duty pending a probe into the incident. An investigation by the Directorate-General of Civil Aviation (DGCA) was also launched.