Devi Ganga, the Hindu goddess of rivers, is worshipped in the Bengali month of Jaishtha with pomp & splendor through out the gangetic Bengal.  According to certain pundits, the celebration is to commemorate the arrival of the river from heaven to the mortal world. 

According to the Puranas (the holy Hindu scriptures), the story goes back to the time when the world was created. The hundred sons of the mythical king, Sagor, were brunt to ashes by the curse of sage Kapil. The only way

their souls could attain liberty was not easy. Their ashes were to be dropped in the holy water of Ganga. But again, Ganga was then a heavenly river & someone had to bring her down to the Earth. So generations after generations, Sagor’s ancestors tried to attain the impossible. At last, Bhagirath, one of his ancestors finally convinced Ganga through his prayers, her necessity in the mortal