As per case facts The appellants challenged the constitutional validity of the amendment to Section of the PVAT Act which extended the limitation period for tax assessment from three years ... to six years retrospectively This amendment sought to overcome prior High Court judgments that had quashed extensions granted by the Commissioner on the technical ground of not serving a prior notice resulting in revenue loss The High Court upheld the amendment and the assessees appealed The question arose whether the retrospective amendment to Section of the PVAT Act extending the period of assessment from three years to six years was constitutionally valid even if the original period of assessment had already expired Finally the Supreme Court upheld the High Court's judgment finding the amendment was neither unreasonable nor excessive Relying on the precedent of Jyoti Traders the Court held that the legislature has the power to enact retrospective laws even in taxation matters and can extend the period of reassessment even if the original period has expired The amendment was designed to undo the effect of earlier adverse judgments by removing the basis upon which they were rendered which is within the legislature's power The appeals were dismissed though the assessees were granted liberty to pursue their appellate remedies without the bar of limitation