Musannaf Ibn Abi Shaybah

Hazrat Hajar bin Anbas Hadrami says that we set out towards Nahrawan with Hazrat Ali (may Allah be pleased with him). When we reached Babylon, the time for Asr prayer arrived. We said, "The time for prayer has come." He remained silent. Then we said, "The time for prayer has come." He remained silent. When he left Babylon, he performed the prayer at that time. Then he said three times, "I did not want to pray in that place where the earth was sunk."

Hazrat Ali (may Allah be pleased with him) considered it undesirable to pray at a place where dung has been thrown.

Hazrat Ibn Abi Mahal says that Hazrat Ali (may Allah be pleased with him) passed by the outskirts of Babylon and did not perform prayer there.