Section 154(5)(a) in The U.P. Zamindari Abolition and Land Reforms Act, 1950
(a)the Registrar or Sub-Registrar appointed under the Indian Registration Act, 1908 before whom any document pertaining to transfer of land is presented for registration comes to know or has reason to believe that the transfer of land is in contravention of Section 154(3) or 154(4)(3); or