Provisional sales tax assessments remain valid where the statute permits prescribed collection and annual final adjustment.

The Kerala General Sales Tax Act's scheme treated sales tax as a yearly levy with final adjustment at year end, but the rule-making power was wide enough to support provisional or periodic assessment and monthly collection during the year. The omission of section 18 and the earlier annual provisional assessment machinery did not invalidate the retained sub-rules (7) to (14) of rule 21, because the Act did not expressly or by necessary implication prohibit such a mechanism. The court therefore upheld those sub-rules as intra vires the Act, and the assessees' challenge failed.

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Issues: Whether sub-rules (7) to (14) of rule 21 of the Kerala General Sales Tax Rules remained valid after the omission of section 18 of the Kerala General Sales Tax Act, 1963, and whether those rules authorising monthly provisional assessments and collection were ultra vires the Act.

Analysis: The Act treated sales tax as a yearly levy, but the scheme of sections 16, 17, 23 and 44 showed that assessment and collection were to be regulated by prescription under the rules, with final adjustment at the end of the year. Section 5 fixed the taxable unit as the financial year, yet it did not exclude provisional ascertainment of liability during the year. The power to prescribe the manner of assessment and collection was sufficiently wide to support rules for periodical provisional assessments and monthly payment, unless the Act expressly or by necessary implication prohibited such a mechanism. The deletion of section 18 and of the earlier annual provisional assessment machinery did not destroy the independent support for rule 21, and the retained sub-rules continued to operate as a valid method of assessment and collection under the rule-making power.

Conclusion: The retained sub-rules (7) to (14) of rule 21 were held to be valid and intra vires the Act, and the challenge by the assessees failed.

Ratio Decidendi: Where a taxing statute confers power to prescribe the manner of assessment and collection and its scheme contemplates final annual assessment with adjustment, the rule-making authority may validly provide for provisional or periodic assessments and collection in advance, unless such power is excluded by the Act.

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