law: The Marine Aids to Navigation Act, 2021
  32. Exemption.-
  The Central Government may, by notification in the Official Gazette, exempt.-
  (a) any ship belonging to the Central Government or any State Government, which is not carrying cargo or passengers for freight or fares; or
  (b) any other ship, or classes of ships or ships performing specified voyages, from the payment of marine aids to navigation dues either wholly or to such extent as may be specified in that notification.