It was later found that the alarm was set off by faulty smoke detectors in the cargo compartment.
IndiGo's Chennai-Kuwait flight carrying more than 160 passengers returned to Chennai airport minutes after taking off in the early hours of Friday when pilots declared a mid-air emergency following a fire alarm.
It was later found that the alarm was set off by faulty smoke detectors in the cargo compartment, said a source privy to the development.
The A320neo plane had taken off around 1.20 am. Just 15 minutes after departure, pilots observed a fire alarm and immediately relayed the emergency code 7700 to all Air Traffic Controls, the source said.
A spokesperson of the airline said, "IndiGo A320 was operating Chennai-Kuwait 6E-1751. After take-off from Chennai, the pilot observed a momentary message of the smoke detector in the aft cargo compartment."
"As a precaution, the pilot returned to Chennai. After arrival it was confirmed that the message was false. The aircraft will be back in operations shortly. Alternate arrangements for all the passengers were made," the spokesperson added.