The foreign national is required to furnish copies of the following documents to open the bank account:
Valid foreign passport.
Valid Indian visa ( it should be a longterm visa: valid for more than 182 days).
Copy of Foreigners Registration Office (FRO) permit.
Indian address proof.
Passport-size photograph.
Copy of PAN card or Form 60.
They also need a letter from employer / admission letter or letter of contract.
RBI Confirmation. It also includes short visits. So they can open accounts.