Around capital, cold and extremely tense atmosphere (7)
I believe the answer is:
climate
'atmosphere' is the definition.
(I've seen this before)
'around capital cold and extremely tense' is the wordplay.
'around' indicates putting letters inside.
'capital' becomes 'lima' (capital of Peru).
'cold' becomes 'c' (eg on taps).
'and' is a charade indicator (letters next to each other).
'extremely' says to hollow out the word (remove centre letters).
'tense' with its middle taken out is 'te'.
'c'+'te'='cte'
'lima' inserted inside 'cte' is 'CLIMATE'.
(Other definitions for climate that I've seen before include "Long-term prevalent weather conditions" , "National weather conditions" , "Came lit (anag.)" , "Lime cat (anag.)" , "The regular weather conditions of a region" .)