Although backed by most EU members, the proposal faces stiff opposition from industry and a handful of governments because of the expected costs and practical difficulties of meeting it.
The suggested standard is about half the 1990 urban background level in major European cities such as London, Milan, and Athens. As the vast majority of benzene emissions come from vehicle exhausts, it will require sharp cuts in areas of dense traffic, where ambient levels are often 3-4 times higher than the urban average.