On 18 June 1996, the European Commission adopted measures under the Auto Oil programme which will result in a 60 to 70% reduction in VOC and NOx emissions from road transport. These emission contribute to the formation of ground-level ozone. A serious problem in the summer, ground-level ozone is a particularly aggressive pollutant formed as a result of complex chemical reactions between primary pollutants and in particular, oxides of nitrogen (NOx) and volatile organic compounds (VOCs). The Auto Oil programme will contribute significantly to this problem of "summer smog". However, during the summer months of 1994 and 1995, the threshold limits for ozone pollution, as set out in Directive 92/72/EEC, were frequently exceeded throughout the Community. In addition, the chemical and physical processes giving rise to ozone formation are highly complex and take place over great distances. This means that ozone is a transboundary problem requiring concerted action: initiatives taken by one country alone may have only a marginal impact. In order to achieve satisfactory air quality with respect to ground-level ozone, the European Commissioner for the environment, Mrs. Ritt Bjerregaard, has therefore called for the Community-wide measures to be complemented by national and local measures such as traffic management schemes, special fuels in highly polluted areas and increased investment in public transport.