Traditional stories tell that Lord Ganesha (or Ganapati) (the names mean "Lord isha or pati of Shiva's hosts gana) was created by goddess Parvati, consort of Lord Shiva. Parvati created Ganesha out of sandalwood paste that she used for her bath and breathed life into the figure. She then set him to stand guard at her door while she bathed. However, while she bathed, Lord Shiva returned and as Ganesha didn't know him, he didn't allow him to enter. Lord Shiva became enraged and severed the head of the child and entered his house. After realizing that he had beheaded his own son, Lord Shiva fixed the head of an elephant (in some versions, Airavata, the vehicle of the god Indra) in place of Ganesha's head. In this way, Lord Ganesha came to be depicted as the elephant-headed God.
The festival is observed in the Hindu calendar month of Bhaadrapada, starting on the shukla chaturthi (fourth day of the waxing moon period). The date usually falls between 20 August and 15 September. The festival lasts for 10 or 12 days, ending on Anant Chaturdashi. This festival is observed in the lunar month of bhadrapada shukla paksha chathurthi madhyahana vyapini