If you have dropped or go to pickup any from the arrival lounge/international departure part of the airport, by driving to the entrance, picking up someone and heading back (without parking) - you end up spending Rs.50 for parking. On the otherhand on the domestic terminal side, one can drop someone and head back without paying (if you do not park). This is how it should be on the other side of the airport as well, but the contractor or Airports authority of India is illegally charging for dropping/picking up someone without parking!
Suggestion: The payment for parking should be at the entry/exit of the parking space and not at the exit of the airport. This will then make it similar to the domestic side of the airport - where you can drop someone and drive away without paying if you do not park.