Imposing area around a Spanish city (7)
I believe the answer is:
Here is my best explanation:
'spanish city' is the definition.
(I've seen this before)
'imposing area around a' is the subsidiary indication.
'imposing' becomes 'grand' (I've seen this before).
'area' becomes 'a' (maths abbreviation).
'around' is an insertion indicator.
'granda' placed around 'a' is 'granada'.
(Other definitions for granada that I've seen before include "Spanish city, site of the Alhambra", "Andalusian city", "City in southern Spain, site of the Alhambra" and "City of Andalusia".)