London's clean air act erases fogs, increases winter sunshine by 50%.

Thanks to the Glean Act, London has not had a thick fog since 1965. Even though there is no simple arithmetic relationship between reduction in smoke concentration and better health, the results in London provide ample justification for the implementation of smoke abatements legislation without waiting for the complete solution of air pollution problems, Sulphur dioxide may have played a large part in the deaths, but is was smoke that was the root cause.