It is clarified that 28% rate [entry 34 (iiia)] applies on admission to a place having casino or race club [even if it provides certain other activities] or admission to a sporting event like IPL. On the other hand, Entry 34 (iii), having a rate of 18%, covers all other cases of admission to amusement parks, or theme park etc or any place having joy rides, merry-go rounds, go-carting etc, whether indoor or outdoor, so long as no access is provided to a casino or race club.
Source: a2ztaxcorp.com