US lawIllinoisRegulationsTitle 35 — ENVIRONMENTAL PROTECTIONCHAPTER I: POLLUTION CONTROL BOARDSUBCHAPTER a: PERMITS AND GENERAL PROVISIONSPart 204 — PREVENTION OF SIGNIFICANT DETERIORATIONSubpart B204.59035 Ill. Adm. Code 204.590ProjectYear: 2026Length: 22 wordsOfficial source Section 204.590 Project "Project" means a physical change in or change in the method of operation of an existing major stationary source.Previous35 Ill. Adm. Code 204.580Next35 Ill. Adm. Code 204.600