Asian city a German visited regularly (4)
I believe the answer is:
agra
'asian city' is the definition.
(Indian city)
'a german visited regularly' is the wordplay.
'visited regularly' indicates alternate letters.
The alternate letters of 'german' are 'gra'.
'a'+'gra'='AGRA'
(Other definitions for agra that I've seen before include "Site of the Taj Mahal" , "mausoleum site" , "tourist centre" , "vicinity of mausoleum" , "Foreign city" .)