Poor say city turned criminal (7)
I believe the answer is:
illegal
'criminal' is the definition.
(similar in meaning)
'poor say city turned' is the wordplay.
'poor' becomes 'ill' (I've seen this in another clue).
'say' becomes 'eg' (both can mean 'for example').
'city' becomes 'LA' (Los Angeles).
'turned' shows that the letters should be reversed in order.
'la' written backwards gives 'al'.
'ill'+'eg'+'al'='ILLEGAL'
(Other definitions for illegal that I've seen before include "Prohibited by law" , "Black-market" , "Ignoring certain acts" , "Forbidden" , "Unauthorised" .)