Section 12(7)(b) in The Integrated Goods and Services Tax Act, 2017
(b)services ancillary to organisation of any of the events or services referred to in clause (a), or assigning of sponsorship to such events,-(i)to a registered person, shall be the location of such person;(ii)to a person other than a registered person, shall be the place where the event is actually held and if the event is held outside India, the place of supply shall be the location of the recipient.