Hasten around capital city (6)
I believe the answer is:
athens
'capital city' is the definition.
(capital of Greece)
'hasten around' is the wordplay.
'around' indicates anagramming the letters.
'hasten' is an anagram of 'ATHENS'.
(Other definitions for athens that I've seen before include "Hasten to the Hellenic city" , "Hasten to European city" , "city in Greece" , "Hasten to Greek city" , "European capital city" .)