A D.C. Circuit has put on hold a challenge to a Trump administration decision to scale back standards for fuel efficiency and greenhouse gas emission for vehicles.  The Trump era rule lowered federal fuel efficiency standard reduction requirements from 5% to 1.5% annually through 2026.  A coalition of mostly democratic lead states sued to overturn the Trump rollback, and the Biden administration argued successfully before the D.C. Circuit to halt the proceedings while the EPA and the National Highway Traffic Safety Administration review the regulations.