Urbanization degrades the environment, according to conventional wisdom. This view has led many developing countries to limit rural—urban migration and curb urban expansion. But this view is incorrect. There are a number of reasons urbanization can be good for the environment, if managed properly. First, urbanization brings higher productivity because of its positive externalities and economies of scale. Asian urban productivity is more than 5.5 times that of rural areas. The same output can be produced using fewer resources with urban agglomeration than without. In this sense, urbanization reduces the ecological footprint. The service sector requires urbanization because it needs a concentration of clients.