(a) The provisions for prevention of significant deterioration of air quality at 40 CFR 52.21 are applicable to the Yavapai-Apache Reservation, pursuant to § 52.21(a).

(b) In accordance with section 164 of the Clean Air Act and the provisions of 40 CFR 52.21(g), the Yavapai-Apache Indian Reservation is designated as a Class I area for the purposes of preventing significant deterioration of air quality.