In the near East did the hygienic conditions in large cities improve, worsen or more or less stay the same after Islam started running things mid way through the first millennium?

by grapp

Places like Babylon or Alexandria always look impressive in illustrations but I have to imagine they smelled of literal shit most of the time. Would early Baghdad or Cairo have been an improvement?

lion_queen

This is an ignorant question as I know very little about Islam, but why would Islam affect hygiene?