Why tamils celebrate Deepavali and light lights everywhere other than because the prince returned for 14 years of exile.
The Killing of Narakasura: Celebrated as Naraka Chaturdasi, two days before Diwali day, it commemorates the killing of Narakasura, an evil demon who created havoc, by Lord Krishna's wife Satyabhama. This happened in the Dwapar Yuga during this time of Lord Krishna's avatar. In another version, the demon was killed by Lord Krishna (Lord krishna provokes his wife Satyabhama to kill Narakasura by pretending to be injured by the demon. Narakasura can only be killed by his mother, Satyabhama) himself.[citation needed] Before Narakasura's death, he requested a boon from his mother, Satyabhama (believed to be an Avatar of Bhudevi - Narakasura' mother), that everyone should celebrate his death with colorful light.
(Note:This is a word for word copy from Wikipedia)
