Delivery making atmosphere fall (7)
I believe the answer is:
airdrop
'delivery' is the definition.
(I know that airdrop is a type of delivery)
'atmosphere fall' is the wordplay.
'atmosphere' becomes 'air' (synonyms).
'fall' becomes 'drop' (synonyms).
'air'+'drop'='AIRDROP'
'making' is the link.
(Other definitions for airdrop that I've seen before include "Parachuting of supplies" , "How paras go in" , "Delivery of supplies by parachute" , "Emergency delivery" , "supplies sent down" .)