Cenvat credit is a scheme that allows manufacturers and service providers to claim a credit for taxes paid on inputs and input services against the tax payable on the final product or service. It aims to avoid double taxation and ensure smooth flow of duties. Under Cenvat credit rules, eligible duties include excise duty, customs duty, and service tax. Credit can be claimed by maintaining proper records and filing periodic returns. Credit wrongly taken can be recovered along with interest and penalties. Key cases discuss eligibility of capital goods and input services for credit claiming.