It's technically not a prohibition, but because the Reserve Bank of India regulates banks and requires a license to deal with anything banking, even if you already have an existing relationship (with other jurisdictions it only penalises marketing into their country which is understandable) with the account holder RBI could just sue us for operating without a licence, and RBI tends to just sue even if you think it's stupid. The resident is never penalised here (unless you have very large stash offshore), it's the bank.

Also, since that some may just scratch their head, here is the relevant provision from MasterCard (https://www.mastercard.us/content/dam/public/mastercardcom/n...).