As usual for the festivals of India, there are multiple stories on why people celebrate Deepa-avali. Here is my story on it. Naraka-asura is is the son of Earth (Bhumi, Aditi) and the Boar (varAha avatar of god Vishnu) that guards the forests of Earth. He got friendship of Mura, a demon that induces vices (of selfishness and self-centrism) in our mind. When he became very powerful he started abusing Aditi, the divine Mother Earth herself. After bearing it all for a very long time, in another eon, Aditi complained to SatyabhAma, the wife of Krishna, the ruler of west of India (while Naraka ruled in other corner, the east of India). Krishna and Satyabhama teamed up, fought and killed Naraka. But before that they have to kill Mura, the demon that induces the vices of selfishness and self-centrism in Naraka's mind. At the time of death (as Mura got killed), Naraka realized his mistake, begged forgiveness and asked for a boon. That people will celebr...