mitigation vs abatement

mitigation and abatement both are nouns.

Word	Noun	Adjective	Verb	Adverb
mitigation	Yes	No	No	No
abatement	Yes	No	No	No

As nouns, abatement is a hyponym of mitigation; that is, abatement is a word with a more specific, narrower meaning than mitigation:

mitigation (noun)	abatement (noun)
to act in such a way as to cause an offense to seem less serious	the act of abating
the action of lessening in severity or intensity	an interruption in the intensity or amount of something
a partial excuse to mitigate censure; an attempt to represent an offense as less serious than it appears by showing mitigating circumstances