Yama Deep Daan is the first day of Diwali celebrations in North India and Gujarat. On Yamadeepdaan day diyas (lamps) are lit all night and this is dedicated to Lord Yama, the Hindu god of death. Yama Deep Daan 2017 date is October 17. In some regions, on the day lamps are also lit and floated down a river or lake. These lamps are dedicated to dead ancestors – for their souls to rest in peace.
The day is also observed as Dhantrayodashi and Dhanvantari Jayanti. In
Maharashtra, Yama Deepdaan is observed on the same day but it is not the first day of the Diwali festival. In this part of India, Diwali begins with Vasu Baras a day before Yamadeepdan.
The popular legend associated with Yama Deepdaan is the story of a young bride who rescues the life of her husband from Lord Yama. The young husband was destined die of snake bite on a particular day. To save her husband, the young bride lit the lamps to divert the attention of Yama who appeared as a snake.
You can read the complete legend of Yamadeepdan here in an earlier article on the same topic.