In plain words
The poet, of Kaṇṭam: So that the immortals might sit in their pride and rule their kingdom, he swings his sword Nandaka and sends to Yama's city the army [of the asuras] that dared to come and fight against them: the city of our Puruṣōttama is the eminent city called Kaṇṭam, on the bank of the Gaṅgā, great in the patience with which it bears the sins of the people of the world who bathe noisily on both its banks, from the Himālaya to the vast sea.