Cess on rubber established an excise levy on domestic production under the Rubber Act by notification. Under section 12(1) of the Rubber Act, 1947 the Central Government, by notification, superseded the earlier notification, appointed an operative commencement date and fixed a unit rate at which an excise duty is to be levied as a cess on all rubber produced in India, operating prospectively except as to things done or omitted before supersession.