1. Rule 86B violation does not automatically trigger Section 50 interest.
Rule 86B restricts utilisation of ITC beyond 99% in specified cases. Section 50 separately requires tax or part thereof to remain unpaid/delayed. Therefore, non-compliance with Rule 86B cannot, by itself, be equated with delayed payment of tax.
2. The 1% need not necessarily be "tax remaining unpaid".
If the taxpayer had eligible ITC sufficient to discharge 100% of the output-tax liability, the tax liability was substantively discharged. The alleged default is in the mode of discharge-100% ITC instead of 99% ITC + 1% cash.
Thus, the Department should establish a statutory basis for treating the 1% as unpaid tax for Section 50 purposes. Rule 86B itself does not automatically deem the 1% to be unpaid tax.
Section 50(3) also should not be mechanically invoked where the ITC was otherwise eligible, since it concerns wrongly availed and utilised ITC.
3. ECL balance is highly relevant.
Where sufficient funds were already credited to the Electronic Cash Ledger on/before the due date and remained available, this materially strengthens the defence against interest. The Arya Cotton Industries line of Gujarat High Court decisions supports the proposition that interest should not accrue merely because the cash-ledger amount was debited later.
However, judicial views on whether mere ECL balance constitutes payment are not uniform; therefore, jurisdiction and the precise ledger chronology matter.
The 10 July 2024 amendment to Rule 88B expressly addresses amounts credited to and remaining in the ECL before the due date. For FY 2022-23, it should not be assumed to apply retrospectively, but it can support the taxpayer's interpretation of the statutory scheme.
Recommended defence
Primary: No Section 50 interest-output tax was fully discharged through eligible ITC; Rule 86B regulates the permitted mode of utilisation and does not automatically establish unpaid tax.
Without prejudice: Even if 1% cash payment was mandatory, amounts already available in the ECL before the due dates materially negate the basis for compensatory interest.
The taxpayer should produce a date-wise ECL reconciliation, challans/CINs, due dates, GSTR-3B dates and subsequent debits, demonstrating that sufficient cash was available and continuously remained in the ledger.
Risk: Rule 86B contravention may be established, but automatic Section 50 interest is reasonably contestable, particularly where the ECL trail is strong.