This document summarizes India's Citizenship Act of 1955 and the history of Indian citizenship. It outlines the key ways Indian citizenship can be acquired: by birth within India to Indian parents; by descent from an Indian parent; through registration if ordinarily resident in India for a number of years; and through naturalization if a foreigner resides in India for 12 years. It also describes the Overseas Citizenship of India and Person of Indian Origin Card programs, as well as exceptions allowing dual citizenship in some cases like children of foreign diplomats born in India.