City haze (4)
I believe the answer is:
smog
'city haze' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for smog that I've seen before include "Man-made atmospheric pollution" , "Polluted atmosphere" , "Dirty mixture of smoke and fog" , "Smoky fog" , "Polluted haze" .)