Bharatiya Nagarik Suraksha Sanhita — Section 58

58. No police officer shall detain in custody a person arrested without warrant for a longer period than under all the circumstances of the case is reasonable, and such period shall not, in the absence of a special order of a Magistrate under section 187, exceed twenty-four hours exclusive of the time necessary for the journey from the place of arrest to the Magistrate's Court, whether having jurisdiction or not.