Why does Oedipus call himself "ungodly pollution"?

is
repeating the phrase used earlier in the play by the blind prophet, . Then, Oedipus had
expressed anger and indignation at such an outrageous description. But by the end of the play,
when the full horror of what he's done finally hits home, Oedipus comes to accept that an
"ungodly pollution" is precisely what he is.

The very presence of
Oedipus in Thebes, this man who's killed his father and married his mother, has brought
spiritual pollution to the city. Inadvertently or not, Oedipus has gone against the will of the
gods. The consequences for him have been truly disastrous, but they could be even worse for the
people of Thebes if Oedipus continues to stick around and pollute the city with his presence.
The only way, then, for Thebes to be cleansed of this ungodly pollution is if Oedipus leaves,
which he does.