According to legend, King Naragasura brutal and often extort people, was defeated and killed by the Great Krishnan. Before dying, the King Naragasura ask all people so that they celebrate victory day as a reminder to those who are good about temptation ghosts and demons, a reminder to those who forget that do good and keep from making mischief among mankind.
Lamps installed in the line can be seen lit in Hindus homes to symbolize the triumph of good over evil is celebrated as Deepavali.
The festival is celebrated for different periods by different communities. Though the core days are common and fall on the same day across Nepal and India, but these days falls on Gregorian months are different depending on the version of the Hindu calendar used in the community. Amanta version ("expire at the moon") Hindu calendar adopted as the Indian national calendar. This calendar was used in southern India and Maharashtra, entertainment six days is carried from the last four days of the month Ashwayuja (Ashwin in Marathi) and the first two days of the new month Kartika. According Purnimanta version ("ends on the full moon") are widespread in northern India, Diwali falls in the middle of Ashwayuja / Ashvin. In the Gregorian calendar, Diwali is usually arrive in October or November.