Whether purchases made by Embassies or UN be taxed or exempted?

It will be taxed, which later on can be claimed as
refund by them.
[The United Nations Organization and Consulates or
Embassies are required to take a Unique Identity Number
and purchases made by them will be reflected against their
number in the return of outward supplies of the supplier
and refunds of taxes can be granted. A separate process
will be notified in the Rules. GST Sec.19 (6)].