You can apply for a transit visa in case you have a connecting flight at Delhi, Mumbai or Chennai airports to a third country. You can apply for a double entry transit visa, in case you are returning by air to Pakistan via any of the three airports mentioned above.
The visa will be valid for stay only in the city of entry for a period not exceeding 36 hours on each visit.
In case you want to apply for a transit visa, you would need to submit the following documents:
1) Valid air ticket, which clearly mentions the flight details as well as the transit time at a particular city in India (transit through Delhi, Mumbai and Chennai only is permitted)
2) Copy of NADRA Card along with its English translation and the translated copy should be notarized.
3) Copy of any utility bill, such as electricity bill/ gas bill/ landline telephone bill (any one as address proof)
If you have a transit visa, you will be required to register only at the immigration checkpost of entry. You will not be required to report your arrival/departure to the registration authority or the nearest police station.
No visa is required for a Pakistani national directly transiting through an Indian airport, provided he/she remains in the area of the airport set apart for international transit passengers.