Diwali is the most important festival of the year in India — and for Hindus in particular.

It is celebrated across faiths by more than a billion people in the world’s most populous nation and the diaspora.

Over five days, people take part in festive gatherings, fireworks displays, feasts and prayer.

Diwali is derived from the word “Deepavali,” which means “a row of lights.”

Celebrants light rows of traditional clay oil lamps outside their homes to symbolize the victory of light over darkness and knowledge over ignorance.

The dates of the festival are based on the Hindu lunar calendar, typically falling in late October or early November. This year, the holiday begins Oct. 20.

While Diwali is a major religious festival for Hindus, it is also observed by Sikhs, Jains and Buddhists. The origin story of Diwali varies depending on the region. All these stories have one underlying theme — the victory of good over evil.