13. Planning area.

(a) alter the limits of the planning area so as to include therein or exclude therefrom such area as may be specified in the notification;
(b) amalgamate two or more planning areas so as to constitute one planning area;
(c) divide any planning area into two or more planning areas;
(d) declare that the whole or part of the area constituting the planning area shall cease to be a planning area or part thereof.