Cenvat credit apportionment: account maintenance or prescribed payment required for mixed use inputs, with limited exemptions. Where Cenvat credit is availed on inputs or input services used both for dutiable and exempted supplies, separate accounts of receipt, consumption and inventory must be maintained and credit taken only for quantities used in dutiable manufacture or taxable services. If separate accounts are not maintained, the supplier must either pay a prescribed percentage of the value of exempted clearances or pay an amount equivalent to the Cenvat credit attributable to such inputs and input services under the apportionment procedures. Specific categories of exempted clearances are excluded from these obligations.