The full form of PIO is People of Indian Origin

Overseas Indians, officially known as Non-Resident Indians (NRIs) or Persons of Indian Origin (PIOs), are people of Indian birth or ancestry who live outside the Republic of India. According to a Ministry of External Affairs report, there are 32 million NRIs and PIOs residing outside India and overseas Indians comprise world’s largest overseas diaspora.^[1] Every year 2.5 million (25 lakhs) Indians migrate overseas, which is the highest annual number of migrants in the world

A person of Indian origin (PIO) means a foreign citizen (except a national of Pakistan, Afghanistan, Bangladesh, China, Iran, Bhutan, Sri Lanka and/or Nepal), who:

• at any time held an Indian passport (but not currently) or
• either of their parents/grandparents/great-grandparents were born and permanently resident in India as defined in 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 (as referred above) or
• is a spouse of a citizen of India or a PIO.