Skill about cladding long gas pipe (7)
I believe the answer is:
trachea
'gas pipe' is the definition.
(tube conveying air to the lungs)
'skill about cladding long' is the wordplay.
'skill' becomes 'art' (both can mean a talent).
'about' shows that the letters should be reversed in order.
'cladding' is an insertion indicator (I've seen this in other clues).
'long' becomes 'ache' (to long for something is to ache for it).
'art' backwards is 'tra'.
'tra' going around 'ache' is 'TRACHEA'.
(Other definitions for trachea that I've seen before include "where air passes" , "body part" , "air passage" , "pipe" , "Tube taking inhaled air from the larynx" .)