5. (1) When the Government is satisfied, after considering the report, if any, made under sub-section (2) of section (4), that the land is needed for a public purpose, a declaration shall be made to that effect under the signature of a Secretary to ¹[the] Government or of some officers duly authorised to certify its orders. (2) The declaration shall be published in the official Gazette, and shall state the district or other territorial division in which the land is situated, the purpose for which it is needed, its approximate area, and, where a plan shall have been made of the land, the place where such plan may be inspected. (3) The said declaration shall be conclusive evidence that the land is needed for a public purpose and after making such declaration, the Government may acquire the land in the manner hereinafter appearing.