Diwali or Deepavali (Tamil: தீபாவளி) is the Hindu festival of lights celebrated every year in autumn in the northern hemisphere (spring in southern hemisphere).
Its celebration includes millions of lights shining on housetops, outside doors and windows, around temples and other buildings in the communities and countries where it is observed.
There is significant variation in regional practices and rituals. Depending on the region, prayers are offered before one or more deities, with most common being Lakshmi – the goddess of wealth and prosperity. On Diwali night, fireworks light up the neighborhood skies. Later, family members and invited friends celebrate the night over food and sweets.
This is from Wikipedia, but I am sure the Indian community on Steemit can explain it a lot better for you! @firepower @things @aishwarya @varunpinto @wandereronwheels etc :D