THis should be informative while choosing shipping method.
THe entry port depends on which postal service is used.
So let me start off, from the info i have:
HK post enters through both Mumbai & Delhi
Singapore post enters through Chennai ( from my experience )
Netherlands post enters Mumbai ( learning that the hard way )
USPS enters Delhi
Royal mail enters Delhi
Sweden post through Delhi
China post ( God forbid ) through Kolkata :
Poland through Mumbai
Request others also to add from their direct shipping tracking experience & i will modify the OP.
To be foolproof, this is not about EMS/UPS/Fedex/DHL etc.