40 CFR § 52.771 - Classification of regions.

---
identifier: "/us/cfr/t40/s52.771"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 52.771 - Classification of regions."
title_number: 40
title_name: "Protection of Environment"
section_number: "52.771"
section_name: "Classification of regions."
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"
---


# 52.771 Classification of regions.

(a) The Indiana plan was evaluated on the basis of the following classifications:

|  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- |
| East Central Indiana Intrastate | II | II | III | III | III |
| Evansville (Indiana)-Owensboro-Henderson (Kentucky) Interstate | I | II | III | III | III |
| Louisville Interstate | I | I | III | III | I |
| Metropolitan Chicago Interstate (Indiana-Illinois) | I | I | I | I | I |
| Metropolitan Cincinnati Interstate | I | II | III | III | I |
| Metropolitan Indianapolis Intrastate | I | I | I | I | I |
| Northeast Indiana Intrastate | II | III | III | III | III |
| South Bend-Elkhart (Indiana)-Benton Harbor (Michigan) Interstate | I | IA | III | III | III |
| Southern Indiana Intrastate | IA | IA | III | III | III |
| Wabash Valley Intrastate | I | I | III | III | III |

(b) The requirements of § 51.150 of this chapter are not met by the classification of counties in APC-22 for the purposes of attainment and maintenance of the total suspended particulate ambient air quality standards.

(c) The requirements of § 51.150 of this chapter are not met by the classification of counties in APC-22 for the purposes of attainment and maintenance of the photochemical oxidant (hydrocarbon) ambient air quality standards.

(d) The requirements of § 51.150 of this chapter are not met by the classification of Jefferson, LaPorte, Porter, Vigo and Warrick Counties in Indiana in Regulation APC-22 for the purposes of attainment and maintenance of the sulfur dioxide ambient air quality standards.

[37 FR 10863, May 31, 1972, as amended at 39 FR 16346, May 8, 1974; 40 FR 50033, Oct. 28, 1975; 41 FR 35677, Aug. 24, 1976; 42 FR 34519, July 6, 1977; 51 FR 40675, Nov. 7, 1986]