Direct tax, means:
(a) any tax chargeable under--
(i) the Income-tax Act;
(ii) the Super Profits Tax Act, 1963;
(iii) The Companies (Profits) Surtax Act, 1964;
(iv) the agricultural income-tax law; and
(b) any other tax which, having regard to its nature or incidence, maybe declared by the Central Government, by notification in the Official Gazette, to be a direct tax for the purposes of this Act. [Payment of Bonus Act, 1965 (21 of 1965), s. 2 (12) (a)]