Air is essential for life but polluted air can kill. In spite of the existing legislation, air pollution remains one of the major environmental problems in Europe. In order to protect its citizens and its environment, Europe needs strict and enforced air pollution legislation. Sector-specific legislation, such as for road vehicles (cars, vans and trucks), diesel machinery (construction machinery, inland water vessels and locomotives) and seagoing ships, is key to achieving clean air in Europe. The EU urgently needs to tighten and improve enforcement of its road, diesel machine and ship emissions legislation.