We conclude that additional investments in cleaner production and products may be stimulated by widening the cost gap between the two types of technologies, for instance, by additionally charging for the use of waste and energy. The potential for continuously substi- tuting end-of-pipe technologies with cleaner technologies might be limited, however, since not all regulations favoring end-of-pipe technologies can be cut down. For example, addi- tional filters currently reduce particulate emissions of Diesel cars more effectively than the more eco-efficient Diesel engines. Thus, a certain amount of end-of-pipe technologies will still be necessary to curb specific emissions which cannot easily reduced.
