(3)Nothing in this section shall authorise the levy by the State Government of any duty which, as between goods manufactured or produced in the [State] [Substituted by M.P. Act No. 23 of 1958.], and similar goods not so manufactured or produced discriminates in favour of the former, or which, in the case of goods manufactured or produced outside the [State] [Substituted by M.P. Act No. 23 of 1958.], discriminates between goods manufactured or produced in one locality and similar goods manufactured or produced in another locality.
