law: 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.