Section 17(2)(iii) in The Registration Act, 1977 (1920 A.D.)
(iii)any debenture issued by any such Company and not creating, declaring, assigning, limiting or extinguishing any right, title or interest, to or in immovable property except in so far as it entitles the holder to the security afforded by a registered instrument whereby the Company has mortgaged, conveyed or otherwise transferred the whole or part of its immovable property or any interest therein to trustees upon trust for the benefit of the holders of such debentures; or