Indian Post Office Act, 1898
26. Power to intercept postal articles for public good
(1) On the occurrence of any public emergency, or in the interest of the public safety or tranquility, the Central Government, or a State Government, or any officer specially authorized in this behalf 25[by the Central or the State Government], may, by order in writing, direct that any postal articles or class or description of postal article in course of transmission by post shall be intercepted or detained, or 26[shall be disposed of in such manner as the authority issuing the order may direct].
(2) If any doubt arises as to the existence of a public emergency, or as to whether any act done under sub-section (1) was in the interest of the public safety or tranquility, a certificate 27[of the Central Government, or, as the case may be, of the State Government] shall be conclusive proof on the point.