The negative impact of large conurbations on the environment, through their rupturing of biogeochemical cycles and unbalancing of the biosphere as a whole, is already the subject of a wide debate. Cities are represented as systems wholly dependent on external resources while at the same time being largely to blame for their depletion, sustaining themselves only by importing vast amounts of material and energy, and – equally damagingly – by exporting a host of different pollutants and waste products. This analysis, issuing from industrial and urban ecology as constituted and formalized since the 1960s, appears to rest on the assumption that such squandering is now part and parcel of industrialization, after two centuries in which urban policy has contributed nothing towards combating the causes and effects of the former, while hygienism, having greatly contributed to the pressures on areas adjacent to cities, has remained oblivious to the impact of the techniques it has adopted.