Section 51A(1)(a) in Chennai City Police Act, 1888
(a)that the movements or acts of any person in the City of [Chennai] [***] [Certain words were omitted by Madras City Police and Tamil Nadu District Police (Amendment) Act, 1985 (Tamil Nadu Act 38 of 1985).] are causing or are calculated to cause, alarm, danger or harm to person or property, or that there are reasonable grounds for believing that such person is engaged or is about to be engaged in the commission of any offence involving force or violence or punishable under Chapters XII, XVI or XVII of the Indian Penal Code (Central Act XLV of 1860) or in the abetement of any such offence; and