40 CFR § 52.2178 - Significant deterioration of air quality.

---
identifier: "/us/cfr/t40/s52.2178"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 52.2178 - Significant deterioration of air quality."
title_number: 40
title_name: "Protection of Environment"
section_number: "52.2178"
section_name: "Significant deterioration of air quality."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "C"
subchapter_name: "AIR PROGRAMS"
part_number: "52"
part_name: "APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 7401"
cfr_part: "52"
---


# 52.2178 Significant deterioration of air quality.

(a) The South Dakota plan, as submitted, is approved as meeting the requirements of part C, subpart 1 of the CAA, except that it does not apply to sources proposing to construct on Indian reservations;

(b) Regulations for preventing significant deterioration of air quality. The provisions of § 52.21 except paragraph (a)(1) are hereby incorporated and made a part of the South Dakota State implementation plan and are applicable to proposed major stationary sources or major modifications to be located on Indian reservations.

[43 FR 26410, June 19, 1978, as amended at 45 FR 52741, Aug. 7, 1980; 59 FR 47261, Sept. 15, 1994; 68 FR 11324, Mar. 10, 2003; 68 FR 74490, Dec. 24, 2003; 72 FR 72621, Dec. 21, 2007]