CENVAT credit denial for construction inputs: service tax credit unavailable where output is immovable property, and reclassification is barred. Renting of immovable property is a taxable service; construction and works contract services used to produce immovable property are inputs but, since immovable property is neither a taxed service nor excisable goods, service tax on those input services cannot be claimed as CENVAT credit. Works contract service value excludes the portion attributable to transfer of property in goods subject to VAT, and excise duty on such goods is not creditable. The composition scheme for works contracts is available only if the option is exercised before payment, and composite contracts cannot be reclassified after the fact to access the scheme.