Retrospective tax notification limits: subordinate legislation cannot enlarge liability absent clear statutory authority.

A notification issued under the Assam General Sales Tax Act could not operate retrospectively from a date earlier than its actual issue because subordinate legislation takes effect prospectively unless the parent statute clearly authorises retrospective operation. The stated earlier effective date therefore could not enlarge tax liability or defeat the concessional rate for the relevant assessment year. The reassessment was also unsustainable because the authority did not independently determine the issue and instead relied on a superior administrative clarification. In a taxing matter, equitable considerations and prior benefit cannot override the statutory mandate.

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Issues: Whether a notification issued under Section 9(3) of the Assam General Sales Tax Act, 1993 could be treated as retrospective from a date earlier than its issue, and whether the reassessment based on a contrary construction and administrative clarification was sustainable.

Analysis: The validity of a notification under the second proviso to Section 9(3) is limited to three years from the date of its issue, and the expression "date of its issue" means the actual date on which the notification is issued. A subordinate legislation cannot be given retrospective effect unless the parent statute authorises it, and no such authorisation existed here. The notification, though stating an earlier effective date, had to yield to the prospective character of the parent provision. The reassessing authority also failed to decide the issue independently and merely acted on the superior authority's clarification. Equitable considerations and past availing of benefit could not override the statutory mandate in a taxing matter.

Conclusion: The notification could not be read retrospectively from the earlier date, and the assessee was entitled to the concessional rate for the assessment year in question; the reassessment and revisional orders were unsustainable.

Ratio Decidendi: Where the parent fiscal provision authorising exemption or reduction is prospective, a notification issued under it cannot operate retrospectively unless the statute clearly permits such retrospective effect, and tax liability cannot be enlarged on equitable grounds.

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