Section 18(1) in Bihar Buildings (Lease, Rent & Eviction) Control Act, 1982
(1)If a tenant in possession of any building, held on a lease for a specified, period, intends to extend the period limited by such lease, he may give the landlord, at least one month before the expiry of the period limited by the lease, a written notice of his intention to do so, and upon the delivery of such notice the said time shall subject to the provision of section 11 be deemed to have been extended by double the period covered by the original lease subject to a maximum of one year only.
