ST. PAUL, Minn. — Minnesota car dealers have lost their legal battle against a state mandate to increase their offerings of zero-emission vehicles. The state Supreme Court decided not to review the car dealers’ case. The dealers had lost earlier before two lesser courts. At issue was Governor Tim Walz’s Clean Car Rule to phase in stricter air pollution requirements. The dealers argued that Walz had cribbed the standards from a California law. This, the dealers argued, violated the state constitution’s prohibition on delegating rule-making authority to another state. With the Supreme Court decision not to consider the case, the lower court’s decision stands. The Minnesota Pollution Control Commission is clear to enforce Walz’s mandate.