Like Aṁśumān himself, Dilīpa, his son, was unable to bring the Ganges to this material world, and he also became a victim of death in due course of time. Then Dilīpa’s son, Bhagīratha, performed very severe austerities to bring the Ganges to this material world.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
दिलीपस्तत्सुतस्तद्वदशक्तः कालमेयिवान् । भगीरथस्तस्य पुत्रस्तेपे स सुमहत्तपः
dilīpastatsutastadvadaśaktaḥ kālameyivān | bhagīrathastasya putrastepe sa sumahattapaḥ
SB 9.9.2