Section 52.1474 - Part D conditional approval(a) The following portions of the Nevada SIP contain deficiencies with respect to Part D of the Clean Air Act which must be corrected within the time limit indicated. 46 FR 21766, Apr. 14, 1981, as amended at 47 FR 15792, Apr. 13, 1982; 47 FR 27069, June 23, 1982; 49 FR 6900, Feb. 24, 1984