ABSTRACT
This chapter shows how air pollution made cities unlivable in the late 19th century, and indeed for large parts of the 20th century. It demonstrates how air pollution and its abatement were constructed in changing ways along with the emergence of the general principles of town planning. Due to environmental legislation that monitored air and water pollution and reduced admissible concentrations of pollutants in regular intervals, the sky above the Ruhr actually could be seen more frequently without smoke clouds. German and European cities and industrial agglomerations came to enjoy blue skies after 1970 due to successful environmental policies, but due even more too economic and technological change. Liveability as a general goal stands in conjunction, as well as in tension, with sustainability, which became an overarching aim of social development after the 1992 Rio environmental summit. Urban planners have adopted sustainable development as a new comprehensive goal of urban planning, evaluating planning measures according to their effects on resources.
