Service area set up somewhere in India (5)
I believe the answer is:
assam
'in india' is the definition.
('Assam' is part of 'india')
'service area set up' is the wordplay.
'service' becomes 'mass' (church service).
'area' becomes 'a' (maths abbreviation).
'set up' is a reversal indicator (in a down clue, letters go up).
'mass'+'a'='massa'
'massa' backwards is 'ASSAM'.
'somewhere' is the link.
This may not be right. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for assam that I've seen before include "place associated with tea" , "Tea state of India" , "Tea-growing state in north-east India" , "Quality cuppa" , "Indian tea growing area" .)