What does the Clean Air Act require states to include in their plans?

The Clean Air Act mandates that states develop and implement State Implementation Plans (SIPs) to ensure compliance with federal air quality standards. These plans must include various strategies and measures aimed at controlling air pollution. Specifically, they must outline how the state will achieve and maintain the national ambient air quality standards, which may involve land use planning and controls to minimize emissions from various sources. This can include regulations on industrial emissions, transportation planning, and other measures that directly impact air quality.

In this context, the need for land use and controls reflects a vital aspect of the Clean Air Act, as careful planning can help reduce pollution levels and improve air quality. The other options, while they may touch on relevant environmental issues, do not directly align with the primary requirements set forth in the Clean Air Act for state air quality planning. Financial subsidies, public education, and modified zoning laws might support broader environmental goals but are not specifically mandated by the Clean Air Act as part of the established SIPs.