The Environmental Protection Agency (EPA) is making a determination that the St. Clair sulfur dioxide (SO<INF>2</INF>) nonattainment area has attained the 2010 primary SO<INF>2</INF> National Ambient Air Quality Standard (2010 SO<INF>2</INF> NAAQS). This determination suspends certain planning requirements and sanctions for the nonattainment area for as long as the area continues to attain the 2010 SO<INF>2</INF> NAAQS. EPA proposed this action on August 17, 2021, and received four supportive comments and one set of adverse comments.