Island of India with casual business area (5)
I believe the answer is:
ibiza
'island' is the definition.
(Spanish island)
'india with casual business area' is the wordplay.
'india' becomes 'i' (phonetic alphabet: alpha, bravo, charlie etc.).
'with' says to put letters next to each other.
'casual business' becomes 'biz' (informal term for business. I am not sure about the 'casual' bit.).
'area' becomes 'a' (maths abbreviation).
'i'+'biz'+'a'='IBIZA'
'of' is the link.
Can you help me to learn more?
(Other definitions for ibiza that I've seen before include "One of the Balearic Islands" , "part of the Balearics" , "resort island" , "One of matching pair" , "Clubbers' island" .)