Check out Monzo in the UK. They started as a top up payment card with great technology. This meant they didn't need a banking license. They are now moving into the current/checking account space with a license.
So do you need a license from the start? Impossible to tell from your comment.
N26 in Germany worked around the same problem by putting the customers actual accounts into an existing bank and just acted as the front-end for those accounts. They later (1-2 years after launch) got their own banking license and moved everyone’s accounts over.
The idea is heavily borrowed from Monzo. A Payment Bank in India seemed like the closest thing to what Monzo did initially. A full banking license requires 5 times more capital than a payment bank.
That is a good question. I'll see if I can still issue cards that links to one real bank account and if we can bypass being a payment bank.
You can re-issue international debit cards and sell them. The vendor will give you API and you build the interface. If you can convert local indian currency to USD, then it can work for you. From there, you get traction and then ask investors for cash.
So do you need a license from the start? Impossible to tell from your comment.