; (bb) such reasonable regulations, policies, and practices as the Secretary concerned determines necessary; and (cc) applicable law (including regulations); and (II) carried out in a manner consistent with the purposes described in subsection (b). (ii) Modification On a determination by the Secretary concerned that grazing within a Tribal cultural area is inconsistent with the purposes for which the Tribal cultural area is established, the Secretary concerned shall modify or terminate the grazing permit or lease, as determined appropriate by the Secretary concerned. (C) Voluntary grazing permit or lease donation program (i) Donation of permit or lease (I) Acceptance The Secretary concerned shall accept the donation of any valid existing permits or leases authorizing grazing on public land, all or a portion of which is within a Tribal cultural area. (II) Termination The Secretary concerned shall terminate any grazing permit or lease acquired under subclause (I). (III) No new grazing permits or leases Except as provided in clauses (ii) and (iii), with respect to each grazing permit and lease donated under subclause (I), the Secretary concerned— (aa) shall not issue any new grazing permit or lease within the grazing allotment covered by the grazing permit or lease; and (bb) shall ensure a permanent end to livestock grazing on the grazing allotment covered by the grazing permit or lease. (ii) Donation of portion of grazing lease (I) In general If a person holding a valid grazing permit or lease donates less than the full amount of grazing use authorized under the permit or lease, the Secretary concerned shall— (aa) reduce the authorized grazing level to reflect the donation