12. Except in so far as in any particular case any privilege or immunity is waived by the Agency, all officials of the International Atomic Energy Agency, other than those referred to in Article 10, shall enjoy —
(a)
immunity from suit and legal process in respect of words spoken or written and all acts done by them in the course of the performance of their official duties; and
(b)
exemption from income tax in respect of emoluments received by them as officers and employees of the International Atomic Energy Agency, provided the officials are not citizens of Singapore.