# Air Plan Approvals; Indiana; Prong 4 (Visibility) for the 2015 Ozone National Ambient Air Quality Standard

**Action Urgency Score:** 30/100

| Field | Value |
|---|---|
| Agency | Environmental Protection Agency |
| Type | Final rule |
| Action | Final rule. |
| Published | 2026-09-09 |
| Effective | 2026-10-09 |
| Significant | No |
| CFR parts | 40 CFR 52 |
| Summary | The U.S. Environmental Protection Agency (EPA) is approving a portion of Indiana's State Implementation Plan (SIP) submission regarding the infrastructure requirements in Clean Air Act (CAA) section 110 for the 2015 ozone National Ambient Air Quality Standards (NAAQS). The infrastructure requirements are designed to ensure that the structural components of each State's air quality management program are adequate to meet the State's responsibilities under the CAA. The EPA finds that Indiana's infrastructure submission fulfills CAA requirements for a State's SIP to contain adequate provisions pr |
| Document number | 2026-18334 |

## Why this score
- Final rule.

Source: Federal Register API (Office of the Federal Register) (https://www.federalregister.gov/documents/2026/09/09/2026-18334/air-plan-approvals-indiana-prong-4-visibility-for-the-2015-ozone-national-ambient-air-quality). Last refreshed: 2026-11-04T21:40:49.974Z.
Data from the Federal Register API; the published Federal Register document is authoritative. Informational only, not legal advice.