Cenvat credit for assignment of rights to use resources spread over multi year period; reassignment permits credit up to tax payable. In rule 4(7) CENVAT credit for service tax on one time charges for assignment of the right to use any natural resource by Government, local authority or any person must be spread evenly over a three year period, with any balance credit on further assignment allowed in the same financial year only to the extent of service tax payable on the consideration for that reassignment. Rule 6(1) Explanation 3 adds that exemption-related activity is eligible only if it has used inputs or input services.