A mid-air altercation onboard IndiGo flight 6E138 from Mumbai to Kolkata on Friday led to a passenger being declared "unruly" and handed over to security upon landing, the airline confirmed.

The incident came to light after a video clip surfaced on social media, showing a seated passenger suddenly slapping a fellow flyer who was standing in the aisle.

The assaulted passenger appeared visibly shaken, with another flyer heard saying he was having a panic attack.

A cabin crew member can be heard trying to calm the situation, saying "don't do", while another passenger asked the attacker, “Why did you slap him? You don’t have the right to hit anybody.”

Sources said the flight, operated by an Airbus A321, landed safely in Kolkata and the accused was taken into custody by airport security officials.

The exact reason for the slap remains unclear, as does the timing of the incident — whether it took place during takeoff or mid-air.

IndiGo, in a statement posted on X, said: “We are aware of an incident involving a physical altercation on board one of our flights. Such unruly behaviour is completely unacceptable and we strongly condemn any actions that compromise the safety and dignity of our passengers and crew.

Our crew acted in accordance with established Standard Operating Procedures. The individual involved was identified as unruly and handed over to the security authorities upon arrival. All appropriate regulatory agencies have been duly informed, in line with protocol.

We remain committed to maintaining a safe and respectful environment on all our flights.”

The number of passengers onboard has not been disclosed. There was no official word on whether further action was taken against the accused.

(With inputs from PTI)