separately vs on an individual basis

separately and on an individual basis both are adverbs.

Word	Noun	Adjective	Verb	Adverb
separately	No	No	No	Yes
on an individual basis	No	No	No	Yes

As adverbs, separately and on an individual basis are synonyms defined as:

Other synonyms of separately include individually, one by one, severally, singly.

separately (adverb)	on an individual basis (adverb)
apart from others	apart from others