The Directorate General of Civil Aviation(DGCA) has come out with a fresh circular making it clear that "in case the airline is compelled to operate a particular flight with a higher capacity aircraft, it shall be ensured that the capacity is restricted to that of the original aircraft".
Such changes in aircraft occur at times when the original plane develops technical problems and cannot undertake its scheduled flight operation.
The maximum number of passengers an airline is allowed to board is detailed under the bilateral air services agreement between the governments of India and other countries.
Though no airline has violated the bilateral agreement norms so far, the sources said the need for such a circular arose after queries raised by some airlines.
A total number of seats, which a designated carrier of any country is allowed to fill in, are dictated by this agreement.
For example, if an Airbus A-320 aircraft, with a capacity to carry around 120 passengers, has to be replaced, the airline can bring in an A-330 that can carry over 250 passengers. In this case, the airline which has changed the plane cannot take more than 120 passengers in the A-330.
Official sources said the DGCA through this latest circular, has made it clear that in case of an emergency when the aircraft needs to be changed, the number of seats or passenger intake cannot be increased by the airline.
This would be limited by the number it is entitled to operate on that particular flight, the sources added.