Vritraghni is a name used to refer to Saraswati River and
Goddess Saraswati in the Rig Veda. The story is associated with killing of
demon Vrita. Legend has it that Demon Vritra removed moisture from earth and
thus making earth dry.
Due to the evil activities of Vritra, the earth became
barren and living beings began to perish. There was death everywhere and no
birth.
Indra subdued the demon Vritra with the weapon Vajra.
Goddess Saraswati assisted Indra in annihilating Demon
Vritra.
For this divine act, Saraswati River is called Vritraghni,
the feminine form of Indra’s epithet Vritrahan.