Passengers were unhurt, said a source. The pilot of the A320 Neo plane issued a 'May Day' call to seek help and some of the passengers were evacuated using emergency chutes on landing.
"The IndiGo aircraft VT ITR was about 45 miles (around 72 km) off Kolkata when the smoke engulfed the aircraft. Amid the passengers' safety in danger, the pilot issued May Day and sought an emergency landing at the Kolkata airport," the source said.
"An IndiGo flight (A320 aircraft) 6E-237 operating on Jaipur-Kolkata route made an emergency landing as a precaution at Kolkata due to suspected smoke in cabin," the airline said in a statement. There was no report earlier of any malfunctioning in the aircraft, it said.
The flight landed safely at Kolkata, it said, adding that on reaching the bay, a few passengers were evacuated via the "aft exit deployed slides" while most passengers deplaned via the front step ladder.
The Airbus A320 Neo planes with Pratt & Whitney engines, which are being operated by budget carriers IndiGo and GoAir, have been frequently facing serious glitches mid-air and on ground since their induction.
The senior official of the Directorate General of Civil Aviation (DGCA) said the "flight made an emergency landing at Kolkata due to smoke in cockpit and cabin".
On landing, the aircraft was taken to an isolation bay, where aft or emergency passenger chutes were deployed and few passengers were evacuated, the official said.
The Aircraft Accident Investigation Board (AAIB), which comes under the Civil Aviation Ministry, has launched a probe into the incident, he said. The airline has also been asked to submit a preliminary report after a detailed technical inspection, he added.