Connecticut has joined New York and California in a multi-state lawsuit that challenges the Trump administration for reducing federal fuel efficiency standards for automobiles.

The new rule by the National Highway Traffic Safety Administration replaces an Obama-era policy. It reduces penalties for automakers that fail to meet what’s known as corporate average fuel economy standards.

Connecticut Attorney General William Tong says the rule is unlawful.

He says it rewards automakers who fail to manufacture fuel efficient vehicles and gives a gift to Trump’s friends in the oil and gas industry.

Last month several automobile manufacturers including Ford, Honda, BMW and Volkswagen voluntarily agreed to California emission standards, which are stricter than the federal standards.