The story
Transliteration of Hindi घर वापसी (ghar vāpsī, literally “to return home”), from घर (ghar, “home”) and वापसी (vāpsī, “return, coming back”). The term owes to the Hindu nationalist ideology that all people of India in ancient times were Hindus, so by converting to Hinduism they were returning to the religion of their ancestors.
Etymology from Wiktionary, CC BY-SA 4.0.