§51.910. What requirements for reasonable further progress (RFP) under sections 172(c)(2) and 182 apply for areas designated nonattainment for the 8-hour ozone NAAQS? — Inbound Citations

As of revocation of the 1997 ozone NAAQS on April 6, 2015, as set forth in § 50.10(c), the provisions of subpart AA shall replace the provisions of subpart X, §§ 51.900 to 51.918, which cease to apply except for § 51.907 for the anti-backsliding purposes of § 51.1105(c)(2). See subpart X § 51.919.

As of April 6, 2015, the provisions of subpart AA shall replace the provisions of subpart X, §§ 51.900 to 51.918, which will cease to apply, with the exception of the attainment date extension provisions of § 51.907 for the anti-backsliding purposes of § 51.1105(d)(2).