(3) The scheme as approved or modified under sub- section (2) shall then be published in the Official Gazette by the State Govern- ment and the same shall thereupon become final and shall be called the approved scheme and the area or route to which it relates shall be called the notified area or notified route: Provided that no such scheme which relates to any inter- State route shall be deemed to be an approved scheme unless it has been published in the Official Gazette with the previous approval of the Central Government.