Notwithstanding anything contained in the Land Acquisition Act, 1894 (1 of 1894), or any corresponding law for the time being in force, no immovable property referred to in section 269C shall be acquired for any purpose of the Union under that Act or such law unless the time for initiation of proceedings for the acquisition of such property under this Chapter has expired without such proceedings having been initiated or unless the competent authority has declared that such property will not be acquired under this Chapter.