OCI Card Registration for Conversion of PIO Card to OCI Card is an online process. OCI Applicants who are having valid PIO Cards may apply from here. Only after complete successful registration, an applicant will be considered as an OCI Card Applicant (In Lieu of PIO-Card).
Non Resident External (NRE) Account is normally being used to keep foreign earnings in Indian Bank Accounts by a person who has status of NRI / PIO / OCI. NRE account should only be used to keep money earned from foreign contry and it should not be used to convert your money earned in India either direct or transfer from your existing bank account such as savings bank account or term deposits or current accounts etc. Non Resident Ordinary (NRO) account is being used to keep the money an NRI / PIO / OCI to manage the income earned in India. NRO account also can be used to keep your earning made from foreign country but remember that it can not be repatriating to its original state, ie., converting into foreign currency.
Many nations permit their citizens to have more than one citizenship enhancing their socioeconomic integration. If you look at the Bible, St. Paul has dual citizenship, one from Tarsus and another from Rome (Acts 22:24-29). Owning second citizenship or multiple citizenship is a step towards more freedom that can give you more control and independence. But, the Indian Constitution does not allow dual or more citizenship to any person of any country.
Here is the list of most wanted abbreviations / acronyms, important terms, and definitions related to NRI / PIO / OCI / OCB. If you find an important item is not listed, please add a comment with its highlights in the field.