A nonattainment area is considered to have air quality worse than the National Ambient Air Quality Standards as defined in the Clean Air Act Amendments of 1970 (P.L. 91-604, Sec. 109). Nonattainment areas must have and implement a plan to meet the standard, or risk losing some forms of federal financial assistance. An area may be a nonattainment area for one pollutant and an attainment area for others.