Proviso substitution in SGST notification aligns exemption reference to statutory proviso, clarifying applicability and effective date. The notification amends the principal State Tax notification by substituting the proviso's reference to the Constitution provision with a reference to the first proviso to sub-section (1) of section 22 read with clause (iii) of the Explanation, thereby changing the statutory basis for exemption applicability; the amendment is effective from 1st February, 2019.