Holika Dahan, or burning of demon Holika, is an important event during Holi festival. On the night before Holi, people light fire with old things, sticks, branches and leaves. Holika Dahan 2017 date is March 12. It symbolizes the victory of good over evil. The bonfire can also be interpreted as a cleansing ceremony to assure in Holi festival.
In remembrance of this event, people lit bonfire known as Holika Dahan.
Legend has it that the Demon king Hiranyakashipu was able to suppress all this subjects and make them his devotees. All his citizens prayed to Hiranyakashipu and not to Vishnu. But Prahalad, the little son of Hiranyakashipu, prayed to Lord Vishnu. He tried all means to stop Prahalad from worshipping Vishnu but he failed.
Hiranyakashipu then decided to kill his son. But each attempt to kill Prahalad was thwarted by Vishnu. Finally, the demon king took the help of his sister Holika. Fire could do nothing to her as she was immune to fire.
So, she took young Prahalad and sat in a huge bowl of fire. But this time young Prahalad came out without any damage and Holika was burnt to death.
The little boy Prahalad was able to overcome evil in the form of Holika through his unwavering devotion to Lord Vishnu.