The Central Government may, if satisfied that it is necessary or expedient so to do on the basis of--
         (a) the information and evidence which has become available to it with respect to the nature and effects of, and the abuse or the scope for abuse of, any substance (natural or synthetic) or natural material or any salt or preparation of such substance or material; and
         (b) the modifications or provisions (if any) which have been made to, or in, any International Convention with respect to such substance, natural material or salt or preparation of such substance or material,
     by notification in the Official Gazette, add to, or, as the case may be, omit from, the list of psychotropic substances specified in the Schedule such substance or natural material or salt or preparation of such substance or material.