Evil can upset a city (8)
I believe the answer is:
valencia
'city' is the definition.
(Valencia is a Spanish city)
'evil can upset a' is the wordplay.
'upset' indicates an anagram.
'evil'+'can'='evilcan'
'evilcan' anagrammed gives 'valenci'.
'valenci'+'a'='VALENCIA'
(Other definitions for valencia that I've seen before include "somewhere in Spain)" , "Spanish port" , "Region and major port of eastern Spain" , "city in Spain?" , "European area" .)