Erin Davis/Axios Visuals Air quality is worsening in the Upper Midwest and Northern California, according to year-over-year data. Why it matters: Poor air quality can lead to long-term health problems ...

“To meet basic standards for healthy air, California has to shift to zero-emissions trucks and trains in the coming years.

California regulators say the Trump administration is unlikely to approve the rules and that they have no choice but to ...