---
kind: "section"
citation: "40 C.F.R. § 52.1921"
title: "40"
number: "52.1921"
heading: "Classification of regions."
url: "https://uscodex.org/cfr/40/52.1921"
---

# §52.1921. Classification of regions.


The Oklahoma plan was evaluated on the basis of the following classifications:


## Notes

### Amendments

[37 FR 10887, May 31, 1972, as amended at 45 FR 9741, Feb. 13, 1980]

### Authority

Authority: 42 U.S.C. 7401 et seq.

### Amendments

[40 FR 5521, Feb. 6, 1975]

### Amendments

[37 FR 10887, May 31, 1972, as amended at 45 FR 9741, Feb. 13, 1980]