The Environmental Protection Agency (EPA) is taking final action to approve, through parallel processing, a revised definition in the State Implementation Plan (SIP) and the Title V Operating Permit Program for the State of Connecticut. On November 30, 2023, the Connecticut Department of Energy and Environmental Protection (CT DEEP) submitted to EPA the State's adopted regulatory amendments to the definition of ``severe non-attainment area for ozone'' for inclusion in the EPA-approved SIP and Title V Operating Permit Program. The revision is necessary to fully implement these programs based on a nonattainment reclassification to a portion of Connecticut for the 2008 ozone National Ambient Air Quality Standard. EPA is approving these revisions pursuant to the Clean Air Act (CAA) and implementing federal regulations.