Air quality in Britain has improved considerably in the last 30 years. Total emissions of __________ (1) in the air have fallen by over __________ (2) since 1960. London and other major cities no longer have the __________ (3) smoke-laden “smogs” of the 1950s and in central London __________ (4) has increased by about 70 percent since the late 1950s. However, __________ (5) have arisen, especially over the emissions from the growing number of __________ (6) and their possible impact on __________ (7). Measures have consequently been adopted to reduce __________ (8) emissions from new vehicles.