<prompt> Translate the following text to EnglishBush alisaini Mabadiliko ya Sheria ya Hewa Safi ya 1990 ambayo ilibadilisha sera ya hewa safi kuhusu masuala ya uchafuzi wa hewa wa kikanda na kitaifa na kuendesha ulinzi wa mazingira katika mwelekeo mpya.  <response>: Bush signed the Clean Air Act Amendments of 1990, it revolutionized clean air policy regarding regional and national air pollution issues and drove environmental protection in new directions. 