The sixth queen raised capital (6)
I believe the answer is:
vienna
'capital' is the definition.
(capital of Austria)
'the sixth queen raised' is the wordplay.
'the sixth' becomes 'VI' (Roman numerals).
'queen' becomes 'anne' (Queen Anne, 18th-century queen).
'raised' says the letters should be written backwards (going up in a down clue).
'anne' written backwards gives 'enna'.
'vi'+'enna'='VIENNA'
(Other definitions for vienna that I've seen before include "somewhere in Austria" , "European city for New Year's Day concert" , "Wien" , "European capital" , "City of Strauss and the waltz" .)