The Ganges is believed to flow in the three worlds: in
heaven it is called Mandakini, on earth the Ganges (or Ganga), and in the
nether region the Bhagirathi. Thus the Ganga is known as "Tripathaga",
or the "Three Path River".
King Bhagirath after performing terrible austerities managed to bring
down the Ganga to this earth. On the tenth day of the bright half of
Jyeshth, Mother Ganga began to flow from heaven to the matted hair of
Shankar, and from the hair of Shankar she began to flow on this earth.
People believe that by bathing in the Ganga sins are washed away. So, the
first ten days of the month Jyeshth (May-June), known as Dashahara, are
dedicated to honour the river Ganges.