# Approval of Air Quality Implementation Plans; California; Regional Haze State Implementation Plan for the Second Implementation Period
> **Rule** · Final rule. · Published 2025-09-05 · Effective 2025-10-06 · 90 FR 42818
## Document
- **Document number:** 2025-17045
- **Category:** air-emissions
- **Federal Register citation:** 90 FR 42818
- **CFR reference:** 40 CFR 52
- **Publication date:** 2025-09-05
- **Effective date:** 2025-10-06
- **State:** CA
- **EPA docket:** EPA-R09-OAR-2025-0203
## Abstract

The Environmental Protection Agency (EPA) is approving the regional haze state implementation plan (SIP) revision submitted by California on August 9, 2022 (hereinafter the "2022 California Regional Haze Plan" or "the Plan"), under the Clean Air Act (CAA) and the EPA's Regional Haze Rule (RHR) for the program's second implementation period. The Plan addresses the requirement that states must periodically revise their long-term strategies for making reasonable progress towards the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility, including regional haze, in mandatory Class I Federal areas. The Plan also addresses other applicable requirements for the second implementation period of the regional haze program. The EPA is taking this action pursuant to CAA sections 110 and 169A.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2025/09/05/2025-17045/approval-of-air-quality-implementation-plans-california-regional-haze-state-implementation-plan-for)
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