Why do South Indians celebrate Diwali a day before North Indians?
Tamils, Telugus and Kannadigas celebrate Deepaavali (not Diwali). Meanwhile Kerala in the south does not celebrate Deepaavali. In Kerala, King Bali's death is associated with this day. The stories behind the Deepaavali in the south and Diwali in the north are different. In the south it is not about Rama returning to Ayodhya, but it is about some Asura (demon) called Narakasura being killed by Krishna or Kali (Sakthi).