According to the popular belief, Mahabali’s homecoming in the month of Chingam is celebrated as ‘Thiru Onam’ annually. Representation pic/AFP

Thiruvananthapuram: As Keralites gear up to celebrate Onam, RSS has triggered a controversy by questioning the legend behind the festival, arguing that it marks the celebration of birth of ‘Vamana’ (incarnation of Lord Vishnu) and not the homecoming of demon king Mahabali.