NRI account types - nre, nro, fcnr
Here is the list of difference between NRO, NRE and FCNR accounts.
NRO - Non Resident Ordinary - Savings/Current, Taxable, Repatriation limit of $1 million
NRE - Non Resident External - Savings/Fixed deposits, Non Taxable, Fully Repatriable
FCNR - Foreign Currency Non Resident - No currency risk, Fixed deposit, Non Taxable, Fully Repatriable
Please note that Existing savings account can be converted to NRO but not to NRE or FCNR
Source of funds deposited in NRO can be from India or out of India but in case of NRE or FCNR, source of funds deposited should be out of India