Post-assessment interest on sales tax applies only after demand notice, not from return-filing due date.

Interest under the West Bengal Sales Tax Act, 1994 was held to depend on the stage at which tax became payable. Section 31 applies to non-payment or delayed payment before assessment, where liability arises on expiry of the return-filing or payment date. Section 32 applies after assessment and operates only if the dealer does not pay the assessed tax and penalty within the time stated in the demand notice. Because the tax was determined only after assessment following detected suppression of sales, interest could not be charged from the due date of filing returns. It became chargeable only after service of the demand notice, and the revisional order was set aside.

---

---

Issues: Whether interest, in a case of post-assessment suo motu revision based on detected suppression of sales, was chargeable under section 31 of the West Bengal Sales Tax Act, 1994 from the due date of filing returns, or only under section 32 after service of the demand notice.

Analysis: Section 31 was held to govern interest for non-payment or delayed payment of tax before assessment, and the liability thereunder arises on the expiry of the prescribed date for filing returns or payment on the basis of returns. Section 32 was held to apply to tax payable after assessment and to operate only where the dealer fails to pay the assessed tax and penalty within the time specified in the notice of demand under section 47. The Court applied the principle that interest is a substantive liability and cannot be fastened from the date of filing of returns on tax determined only upon final assessment, particularly where the demand arises after assessment proceedings and service of notice.

Conclusion: Interest could not be levied under section 31 from the due date of filing returns. It was chargeable only after service of the demand notice under section 32. The impugned order was unsustainable.

Final Conclusion: The application succeeded and the revisional order was set aside, with the authority directed to proceed in accordance with law.

Ratio Decidendi: Interest on sales tax determined after assessment is not recoverable from the date of filing returns under the pre-assessment interest provision, but only in accordance with the post-assessment demand mechanism after service of notice.

---