A light breeze back in the valley (3)
I believe the answer is:
ria
'valley' is the definition.
(I've seen this before)
'a light breeze back' is the wordplay.
'a light breeze' becomes 'air' (I've seen this before).
'back' shows that the letters should be reversed in order.
'air' backwards is 'RIA'.
'in the' is the link.
(Other definitions for ria that I've seen before include "Irish academy for sciences and humanities, in short" , "inlet between hills" , "Institution for the promotion of art, in short" , "Coastal inlet" , "Little girl" .)