He tackles burning issues (7)
I believe the answer is:
fireman
'he tackles' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'burning issues' is the wordplay.
'burning' becomes 'fire' (fire is a kind of burning).
'issues' becomes 'man' (I can't justify this - if you can you should believe this answer much more).
'fire'+'man'='FIREMAN'
Can you help me to learn more?
(Other definitions for fireman that I've seen before include "Emergency services worker" , "Red engine driver" , "Locomotive stoker" , "Fighter of blaze" , "In frame (anag.)" .)