Hi,
United Nations is an Organisation created under a Charter signed by all member countries.
UNICEF is a programme of United Nations Organisations.
Article 105 (2) and (3) of the United Nations Charter specify that
"2. Representatives of the Members of the United Nations and officials of the Organization shall similarly enjoy such privileges and immunities as are necessary for the independent exercise of their functions in connexion with the Organization.
3.The General Assembly may make recommendations with a view to determining the details of the application of paragraphs 1 and 2 of this Article or may propose conventions to the Members of the United Nations for this purpose."
In pursuance of power vested under Article 105(3) the UN Charter, the body has adopted convention where in it has in Section 18 (b) of Article V of the Convection on the Privileges and immunities of the United Nations has specified that
Officials of the United Nations shall:
(b) Be exempt from taxation on the salaries and emoluments paid to them by the United Nations;
India being a member of the United Nations has passed United Nations (Privileges and Immunities) Act, 1947 incorporating therein the UN Convention.
Exemption from Indian Income Tax of Employees salary is specified under the same Article of the Indian Act as that of the Convention viz. Article V of Section 18(b).
UNICEF being a programme of United Nations, salaries received by UNICEF Employees is exempt from tax in India.
Gopal..