# Approval and Promulgation of Implementation Plans
> **Rule** · — · Published 2021-05-25 · 86 FR 27981
## Document
- **Document number:** 2021-11116
- **Category:** other
- **Federal Register citation:** 86 FR 27981
- **CFR reference:** 40 CFR 52
- **Publication date:** 2021-05-25
## Source
- [Federal Register document](https://www.federalregister.gov/documents/2021/05/25/2021-11116/approval-and-promulgation-of-implementation-plans)
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