Cities and local governments are at the forefront of cutting air pollution, using new policy levers to limit dirty vehicle traffic and improve zoning rules to address environmental injustice.

For example, European cities are adopting ultra-low and zero-emission urban access zones, keeping dirty vehicles out of their busy central districts; Chinese cities have deployed more than 400,000 electric buses, and Columbus, Ohio, is teaching other cities how to detoxify municipal transportation.

Meanwhile, other cities have noted how construction sites can unwittingly create pollution hotspots and are requiring that crews use diesel-emission control technology on both on- and off-road vehicles involved in the projects.

In addition, data can help cities change land use policies that have allowed for polluting industries to open their doors in low-income areas and within communities of color, disproportionately burdening the health and well-being of residents.