Wine area with a lot of activity (4)
I believe the answer is:
asti
'wine area' is the definition.
(Italian commune known for its wine)
'with a lot of activity' is the wordplay.
'with' means one lot of letters go next to another.
'lot of' means to remove the last letter (a lot of the word but not all of it).
'activity' becomes 'stir' (stir can mean activity or fuss).
'stir' with its last letter removed is 'sti'.
'a' put next to 'sti' is 'ASTI'.
(Other definitions for asti that I've seen before include "Italian town, famous for its wine" , "town in Italy" , "Source of fizz" , "Italian 'sparkler'" , "Italian drunk" .)