M/S. KRISHNAMURTHI & CO. ETC. vs STATE OF MADRAS & ANR.

The Supreme Court upheld the validity of the retrospective imposition of sales tax on mineral oils, including furnace oil, under the Madras General Sales Tax Act, as amended. The Court held that legislative power allows for both prospective and retrospective laws, including the validation of previously invalid laws, as per Section 4 of the Act. The Court found that the amending Act was a legitimate exercise of legislative power and did not violate Articles 14 and 19 of the Constitution, affirming the High Court's dismissal of the writ petitions.