Ved

Vedic version is that Ganga is formed when Indra slays the water-holding demon Vritta.

Death of Vritta releases the waters that he had covetously kept for himself, thus is born Ganga.

Then, Bhaghiratha the descendent of a king who can only get mukti if his ashes are scattered in ganga prays a lot to Shiva.

Shiva agrees and holds the tremendous force of Ganga falling from heaven directly on his jata (matte hairs).

Note : Vishnu puran.. as always has its own version Because ganga has appeared many times at many places

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