Excise duty on spun yarn follows the removal date, with exemption limited to the notification's own time-bound scope.

Excise duty on spun yarn was governed by the rate in force on the date of removal, not the date of manufacture. The SC noted that the earlier exemption notifications applied only to spun yarn used in the manufacture of fabrics before 15 July 1977, while yarn cleared on or after that date fell under the later notification. On that basis, the appellant remained liable to duty under the later regime, and the refund claim succeeded only to the limited extent covered by the earlier exemption window.

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Issues: Whether excise duty on spun yarn manufactured during one period but cleared after a later notification was chargeable at the rate prevailing on the date of removal, and whether the appellant was entitled to refund or exemption under the earlier notifications.

Analysis: The appeal concerned duty on cotton/cellulosic spun yarn manufactured between 18 June 1977 and 15 July 1977 but cleared on or after 15 July 1977. The controlling principle applied was that duty is chargeable according to the rate in force when the goods are removed. The prior notifications granting exemption were available only to spun yarn used for manufacture of fabrics before 15 July 1977. For yarn cleared after that date, the later notification governed liability.

Conclusion: The appellant was liable to pay excise duty on the basis of the later notification, and the refund claim was not sustainable except to the limited extent covered by the earlier exemption for yarn used in fabrics before 15 July 1977.

Ratio Decidendi: Excise duty is payable at the rate in force on the date of removal of the goods, and exemption under a notification operates only within its own temporal and substantive limits.

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