This article discusses the colonial policies around public health, sanitary measures and control of venereal diseases in the Madras Presidency in the 1860s and 1870s, and describes how these policies shaped urban development of Madras. It investigates how British colonial measures to curtail venereal diseases concurred with concerns about ‘public health’ in the 1860s and 1870s in the Madras Presidency and the city of Madras. It questions the extent to which British ‘public health’ policies encompassed the Indian population. Although there is a recent increase in scholarly interest in studying the medical and sanitary history of the Madras Presidency, very few historians have focused on the ways in which colonial morality influenced town-planning and sanitary policies in the area. Earlier, scholars believed that segregation was key to maintaining public health in colonial cities; however, recent scholarship has questioned the notions of ‘dual city’ by highlighting the blurred lines. This article also investigates how far the colonial administration successfully segregated the European population from the Indian population and the Indian labouring and service-providing poor from the non-labouring poor.