Air India Express passenger plane overshot the runway and broke into two after landing
The Boeing-737 flight from Dubai was flying home Indians stranded overseas due to pandemic.
There were 174 passengers, 10 infants, 2 pilots and 4 cabin crew on board the aircraft.
Plane's fuselage sheared apart as it fell into a valley 30 feet below.
The Kerala state police chief said at least 15 people had been killed.
At least four passengers are still stuck in the wreckage.
The plane, part of the Vande Bharat Mission to repatriate Indian nationals from overseas during the coronavirus lockdown.
According to officials of the Kerala Police, scores of people have been reported injured and at least 100 shifted to various hospitals nearby. It had been raining heavily at the time of the accident.
India's top aviation body, the Directorate General of Civil Aviation (DGCA), has ordered a detailed inquiry into the matter. It said the plane broke into "two pieces" after landing at the airport.
The prime minister announces Rs 2 lakh compensation for the families of those who have died in the crash, and Rs 50,000 for those injured.
The co-pilot is also among those dead.