The sanitary movement was an approach to public health first developed in England in the 1830s and '40s. With increasing industrialization and urbanization, the removal of filth from towns and cities became a major focus in the struggle against infectious diseases. As pioneered by Edwin Chadwick, the sanitary movement also embraced an explicit political objective, according to which urban cleansing took on a figurative as well as a literal sense, and was seen as a potential solution to the threat posed by the "dangerous classes." European cities followed suit, with Paris and Naples embarking on wholesale rebuilding projects, necessitating large-scale state intervention. Although these technological reforms marked an undeniable step forward for public health, they often also entailed the exclusion of other strategies, such as progressive economic and educational reforms.