Section 3(15)(i) in The Defence of India Act, 1962
(i)the apprehension and detention in custody of any person whom the authority empowered by the rules to apprehend or detain (the authority empowered to detain not being lower in rank than that of a District Magistrate) suspects, on grounds appearing to that authority to be reasonable, of being of hostile origin or of having acted, acting, being about to act or being likely to act in a manner prejudicial to the defence of India and civil defence, the security of the State, the public safety or interest, the maintenance of public order, India’s relations with foreign States, the maintenance of peaceful conditions in any part or area of India or the efficient conduct of military operations, or with respect to whom that authority is satisfied that his apprehension and detention are necessary for the purpose of preventing him from acting in any such prejudicial manner,