Urban haze (4)
I believe the answer is:
smog
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">urban haze</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for smog that I've seen before include "Smoky haze" , "Smokey fog" , "Dirty mixture of smoke and fog" , "Thick polluted mist" , "Fog and smoke mix" .)