Input Tax Credit reconciliation: procedural verification and evidence requirements to address ITC GSTR3B vs GSTR2A discrepancies. Proper officers must obtain invoice-level details for ITC claimed in GSTR-3B but not reflected in GSTR-2A and verify fulfillment of eligibility conditions for ITC: possession of tax invoice/debit note, receipt of goods or services, and payment to the supplier. Officers must also assess need for reversal for ineligible ITC and compliance with time limits. To verify tax payment by suppliers, certificates with UDIN from chartered/cost accountants are required above a specified threshold; supplier certificates suffice below that threshold. The guidance applies to bona fide errors for FY 2017 18 and 2018 19 in ongoing proceedings only.