Gst on foreign tour operator

Hi,

Please any one clarify my doubt, My client is doing foreign tour operator services (Haj Tour- Saudi Arabia) to indian resident.
He is collecting money form his client for booking air ticket through air travel agent, visa and accomodation at abroad.
The above services is taxbale or not.? 1. If taxable, for which amount i have to coniser as taxable value? 
2. can i adjust GST credit? Kindly clarify my doubt asap.
Thanks in advance.