Artist hosting one West Indian festival (6)
I believe the answer is:
diwali
'indian festival' is the definition.
(festival in Hinduism)
'artist hosting one west' is the wordplay.
'artist' becomes 'dali' (Salvador Dali).
'hosting' is an insertion indicator (inserted letters are welcomed in or hosted).
'one' becomes 'i' (Roman numeral).
'west' becomes 'W' (abbreviation).
'i'+'w'='iw'
'dali' going around 'iw' is 'DIWALI'.
(Other definitions for diwali that I've seen before include "religious festival" , "Light festival" , "Hindu festival; I'd wail (anag.)" , "Festival in honour of Lakshmi" , "Hindu festival of lights" .)