Woah! Think Beijing is smog-choked? Well NYC used to be just as bad (Source: EPA photo.) Many Americans have forgotten just how smoggy many of our cities were until Nixon signed the Clean Air Act in 1970. It took some time to really get off the ground, but its positive effects today are crystal clear. So why then do the Koch brothers and the Republican Tea Party want to take us back to a time before sensible air pollution controls?