Atmosphere old boy found in province and capital (7)
I believe the answer is:
nairobi
'capital' is the definition.
(Nairobi is an example)
'atmosphere old boy found in province' is the wordplay.
'atmosphere' becomes 'air' ('air' can be a synonym of 'atmosphere').
'old boy' becomes 'ob'.
'found in' is an insertion indicator.
'province' becomes 'ni' (I've seen this in other clues).
'air'+'ob'='airob'
'airob' put inside 'ni' is 'NAIROBI'.
'and' is the link.
(Other definitions for nairobi that I've seen before include "East African capital" , "Badly-behaved child" , "Kenya's capital city" , "I, a robin (anag) - city" , "The capital of Kenya (7)" .)