Small feline in urban haze (4)
I believe the answer is:
smog
'urban haze' is the definition.
(I've seen this in another clue)
'small feline' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'feline' becomes 'mog' (I am not sure about this - if you are sure you should believe this answer much more).
's'+'mog'='SMOG'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for smog that I've seen before include "Smoky fog" , "Pollutant fog" , "Fog and smoke mix" , "Fog polluted by smoke" , "Man-made atmospheric pollution" .)