Input Tax Credit reconciliation restricts ITC where supplier reporting is absent and governs treatment in pending proceedings. Clarification governs reconciliation where ITC availed in Form GSTR-3B exceeds Form GSTR-2A for 1 April 2019-31 December 2021, affirming that rule-based additional credit was permissible only subject to the statutory payment condition for ITC and within specified rule limits for successive subperiods; it applies earlier guidance for pre-rule months, illustrates allowed and disallowed excesses where limits are breached, notes cumulative adjustment provisos for specified months, and states that from 1 January 2022 ITC is admissible only if reported by suppliers and communicated in Form GSTR-2B.