PIO
A Person of Indian Origin (PIO) means a foreign citizen (except a national of Pakistan, Afghanistan Bangladesh, China, Iran, Bhutan, Sri Lanka and Nepal) who at any time had previously held an Indian passport.
Or either of their parents/ grandparents/ great grandparents was born and permanently resident in India as defined in the Government of India Act, 1935 and other territories that became part of India thereafter provided neither was at any time a citizen of any of the aforesaid countries.
Or who is a spouse of a citizen of India or a PIO
OCI
A foreign national, - (i) Who was a citizen of India at the time of, or at any time after 26th January 1950