Becomes clear, American city follows crime (7)
I believe the answer is:
larceny
'crime' is the definition.
(larceny is a kind of crime)
'becomes clear american city follows' is the wordplay.
'becomes' indicates anagramming the letters (I've seen 'become' mean this).
'american city' becomes 'ny' (I've seen this in other clues).
'follows' is a charade indicator (letters next to each other).
'clear' with letters rearranged gives 'larce'.
'larce'+'ny'='LARCENY'
(Other definitions for larceny that I've seen before include "Legal term for theft" , "Criminal activity" , "taking offence" , "Burglary" , "crime" .)