(1) Notwithstanding the provisions of section 3, supply of goods or import of goods specified in the
Sixth Schedule shall, subject to such conditions as may be specified by the Federal Government,
be exempt from tax under this Act.
(2) Notwithstanding the provisions of sub-section (1) --

(a) the Federal Government may, by notification in the official Gazette, exempt any
taxable supplies made (***) or any goods or class of goods, from the whole or
any part of the tax chargeable under this Act, subject to the conditions and
limitations specified therein; and

(b) the Board may, by special order in each case stating the reasons, exempt any import or supply of goods of such description or class, as may be specified from the payment of the whole or any part of the tax chargeable under this Act.

(3) The exemption from tax chargeable under sub-section (2) may be allowed from any previous date specified in the notification issued under clause (a) or, as the case may be, order made under clause (b) of that sub-section.

(4) Where a person does not desire to avail any tax exemption, he may, after voluntary registration, opt to pay sales tax at the rate applicable to such supplies under the provisions of section 3 subject to condition that he shall not thereafter be de-registered till the expiry of two years from the date of such registration.