On March 20, 2023, Indiana submitted a revised CAA section 111(d) state plan for implementing the revised emission guidelines for Municipal Solid Waste (MSW) Landfills. The enforceable mechanism for this state plan is a state rule codified in 326 Indiana Administrative Code (IAC) 8-8.2. The rule was adopted on September 14, 2022, and became effective on March 10, 2023.