Charak Puja also known as Nil Puja is a Hindu folk festival held in southern Banhladesh and West Bengal on the last day of the month of Chaitra in Bengali calender called Choitro. 

People believe that the festival will carry prosperity by eliminating the sorrow and sufferings of the previous year. The festival is actually a festival to satisfy Load Shiva, the great Debadideb of Hindu Religion. Though the festival takes place on the mid night of Chaitra Songkranti, the preparation phase usually starts before one month of the day. In Bangladesh, it is frequently found to take place at Thakurgaon, Patuakkhali,Gazipur, Dhaka and other district in villages and cities.  

Though the festival takes place on the mid night of Chaitra Songkranti, the preparation phase usually starts before one month of the day. The arrangement team of the festival go from village to village to procure the necessary components like paddy, oil, sugar, salt, honey, money and other items with the arranged cosmetics such as Shiva, Parvati and Narod.On midnight of the Songkranti, the worshippers are gathered together to worship the God and after puja the or asad is distributed.