To me, "Manga" in Chinese is Manhua (ok, in Cantonese, or maybe it's the same pinyin for Mandarin!). And there is an exhibition held in London right now! I found out via this interesting article from the Beeb.
Location: London College of Communication, Elephant & Castle
And it's called Manhua! China Comics Now. If you are in London, the exhibition ends on April 11th.