Eternity

[Belacqua]

. There is no section for "impurity."

There is a section because impurity in Catholicism means lust.

In the Inferno, the circle for the lustful is the highest, least bad level. Paolo and Francesca. 

In the Purgatorio, the purification of lust is the last stop before the Earthly Paradise, because to Dante lust is the least bad of sins. The lowest, worst sin is pride. Pride makes all other sins possible.

For Dante, sin is always a misdirection of love. Loving other people too much is far less evil than loving, say, money or fame, because people are made in the image of God and we are right to love them. 

Whoever said that the punishment for lust in Dante is the worst had never read the book.