A Jet Airways flight returned to Mumbai, India's financial capital, on Thursday after dozens of passengers complained of ear pain and nose bleeding due to the loss in cabin pressure.
An airline statement said Flight 9W697 with 166 passengers and five crew members landed normally in Mumbai. Medical help was given to 30 passengers.
Oxygen masks were deployed during the emergency aboard the Boeing 737, said Darshak Hathi, a passenger.
According to Flightradar24 aviation tracking site, the plane stopped climbing at 11,000 feet (3,350 meters) before returning to Mumbai.
Hathi also said there was a problem with the plane's air conditioning after it took off from Mumbai.
The Press Trust of India news agency quoted an official as saying the malfunctioning occurred during the plane's climb. The plane was heading to Jaipur, a tourist destination and the capital of Rajasthan state.
The airline said the flight's cockpit crew was taken off scheduled duties pending an investigation.