It may be necessary, in order that future (51) can enjoy clean air, that more of the (52) is borne by long-term central government funD、As air pollution varies enormously from place to place and can, indeed, be very local, it may also be necessary for the central government to (53) money so that local authorities can (54) special local problems. That these can be significant was shown by the report made in 1970 (55) behalf of the LondonBoroughsAssociation. This (56) that in central London since 1958 smoke concentrations have decreased by 80 percent, whereas sunshine has increased by 70 percent and winter visibility has (57) threefolD、There have been (58) in mortality and hospital admissions (59) with air pollution and in the response to it of bronchitis, as well as clear if less documented increases in plant types and bird (60) in the cities.