Charak Puja (also known as Cadak, and Nil Puja) is a Hindu folk festival in honour of the god Shiva. It's held in southern Bangladesh and West Bengal on the last day (Songkranti) of the month of Chaitra (Choitro in the Bengali calendar), at midnight.People believe that by satisfying Shiva, the festival will bring prosperity by eliminating the sorrow and sufferings of the previous year.In the picture a devotee is being inserted with a iron rod through his tongue by the priest.