Blight in urban environment (4)
I believe the answer is:
bane
'blight' is the definition.
(bane is a kind of blight)
'in urban environment' is the wordplay.
'in' indicates the answer is hidden within the clue.
'BANE' is hidden in the letters of 'urban environment'.
(Other definitions for bane that I've seen before include "Source of misery" , "Cause of distress, ruin" , "scourge" , "Cause of trouble or anxiety" , "Something causing misery or distress" .)