A cartel accepts too much corruption (7)
I believe the answer is:
rotting
'corruption' is the definition.
The answer and definition can be both natural processes as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'a cartel accepts too much' is the wordplay.
'a cartel' becomes 'ring' (both can mean a criminal group).
'accepts' is an insertion indicator.
'too much' becomes 'OTT' (short for over the top).
'ring' enclosing 'ott' is 'ROTTING'.
Can you help me to learn more?
(Other definitions for rotting that I've seen before include "corruption?" , "Going bad" , "Decaying" , "Putrid" , "Sultanate in NW Borneo" .)