Country's air has rising carbon monoxide, with articles describing dead (1,6)
I believe the answer is:
o canada
'country's air' is the definition.
(Canadian national anthem - air can mean a tune)
'rising carbon monoxide with articles describing dead' is the wordplay.
'rising' is a reversal indicator (going up in a down clue).
'carbon monoxide' becomes 'CO' (chemical formula for carbon monoxide).
'with' says to put letters next to each other.
'articles' becomes 'ana' ('an' and 'a', English indefinite articles).
'describing dead' becomes 'da' (I can't justify this - if you can you should give a lot more credence to this answer).
'co' back-to-front is 'oc'.
'oc'+'ana'+'da'='O CANADA'
'has' acts as a link.
(Other definitions for o canada that I've seen before include "patriotic song" , "National anthem" .)