Administrative Law. Nondelegation Doctrine. D. C. Circuit Holds That EPA Construction of Clean Air Act Violates Nondelegation Doctrine. American Trucking Ass'ns, Inc. v. EPA, 175 F.3d 1027 (D. C. Cir. 1999), Modified, 195 F.3d 4 (D. C. Cir. 1999)