More than 30 Indian passengers, some bleeding from their noses and ears, have received treatment after pilots ‘forgot’ to turn on a switch regulating cabin pressure, officials said.
Jet Airways flight 9W 697 from Mumbai to Jaipur turned back shortly after take off.
Videos tweeted by passengers aboard the plane showed oxygen masks deployed inside the aircraft.
The Boeing 737, which was carrying 166 passengers, landed safely.
The aviation ministry has said the cockpit crew has been taken off duty pending investigation.