If any land reserved, allotted or designated for any purpose specified in any plan under this Act is not acquired by agreement within ten years from the date on which a final Regional plan, or final Development plan comes into force or if proceedings for the acquisition of such land under this Act or under the Land Acquisition Act, 1894, are not commenced within such period, the owner or any person interested in the land may serve notice on the Planning Authority, Development Authority or as the case may be, Appropriate Authority to that effect; and if within six months from the date of the service of such notice, the land is not acquired or no steps as aforesaid are commenced for its acquisition, the reservation, allotment or designation shall be deemed to have lapsed, and thereupon the land shall be deemed to be released from such reservation, allotment or designation and shall become available to the owner for the purpose of development or otherwise, permissible in the case of adjacent land under the relevant plan.