An IndiGo plane that took off from Delhi for Doha was diverted to Karachi on Sunday night after a passenger fell ill onboard, officials said.
The passenger, a Nigerian national aged around 60, was later declared dead on arrival, they said.
The officials said the aircraft, A320-271N, which was parked at the Karachi airport for nearly five hours, returned to Delhi after the authorities in Karachi issued the death certificate of the passenger and all formalities were completed.
An IndiGo spokesperson on Monday said the flight, 6E-1736, operating from Delhi to Doha (Qatar), was diverted to Karachi (Pakistan) due to a medical emergency on board.
"Unfortunately, on arrival, the passenger was declared dead by the airport medical team," the spokesperson said in a statement.
"We are deeply saddened by the news and our prayers and wishes are with his family and loved ones (of the deceased passenger)," the spokesperson said.
Pakistan Civil Aviation Authority officials in Karachi said the passenger fell ill onboard and the captain requested an emergency landing at the Jinnah International Airport.
Doctors from the health department were sent to provide treatment but the passenger had passed away. After the death certificate of the passenger was issued and all formalities were completed, the plane returned to Delhi, the officials said.
A Delhi Police officer said the body of the passenger has been handed over to his family members.
The total number of people onboard the aircraft could not be immediately ascertained.