Knowing that she was pregnant, the co-wives of the wife of Bāhuka conspired to give her poison with her food, but it did not act. Instead, the son was born along with the poison. Therefore he became famous as Sagara [“one who is born with poison”]. Sagara later became the emperor. The place known as Gaṅgāsāgara was excavated by his sons.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
आज्ञायास्यै सपत्नीभिर्गरो दत्तोऽन्धसा सह । सह तेनैव सञ्जातः सगराख्यो महायशाः
ājñāyāsyai sapatnībhirgaro datto'ndhasā saha | saha tenaiva sañjātaḥ sagarākhyo mahāyaśāḥ
SB 9.8.4