on an individual basis vs individually

on an individual basis and individually both are adverbs.

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

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

Other synonyms of on an individual basis include one by one, separately, severally, singly.

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