South India · Kerala; ThrikkakaraFolkMalayalam-speaking Kerala
The Onam songs of Kerala describe a reign in which everyone was equal, nobody cheated, and no one went hungry. That reign was Mahabali's, and it ended when Vishnu, taking the form of a small Brahmin, asked the king for as much land as three of his steps would cover. Two strides took the worlds; for the third the king bowed his own head, and was sent down beneath the earth. The story's Kerala turn is what happens next: the king asks to come back once a year, and the state keeps that appointment at harvest with flower carpets, new clothes and the Onam feast. The Vamana temple at Thrikkakara, whose name is taken to mean the place of the sacred foot, is held to mark the spot, and its records are cited for an organised festival as early as the ninth century. Tradition holds the exile-and-return story as its own; the political argument about what the Puranas 'really' say is recent.
In the Bhagavata's eighth book Bali's generosity earns him Vishnu's favour: after the three steps the god sends him to rule Sutala, a realm said to be better than heaven, and promises to stand guard at his door. The Deccan keeps the same story as Bali Padyami on the Diwali calendar.
What is different here:
The Purana ends in a blessing and a new kingdom; the Kerala telling ends in exile softened by a yearly homecoming, with no mention of Sutala. The political dispute of 2016 onward turns on exactly this difference, and scholars note that both readings have textual and regional footing.
Sources: The legend of Mahabali (Onam); Thrikkakara charitham; Thrikkakara Temple — Wikipedia; The asura who won hearts: Kerala's Onam and its subversive significance; The origin of Onam; Srimad Bhagavatam (Bhagavata Purana); What is the story of King Mahabali in relation to Onam? — Britannica; The RSS attempt to rewrite Onam