The lawsuit filed May 27 by California, Michigan, Colorado and other states objects to an April rule published by the federal Environmental Protection Agency that would raise the minimum corporate average for passenger car fuel economy by 1.5 percent annually through 2026. The previous rule required the minimum level to rise 5 percent annually over that period. Obama’s schedule would have raised the level to 46.7 miles per gallon in 2026, while the new rules would reach 40.4 mph.

The EPA called the new rules a responsible balance between protecting the environment and the interests of automakers and consumers. The states suing the administration, joined by four cities, contend that the new rules are based on faulty science and do too little to protect the environment.

Last year Trumps administration declared it was revoking California’s ability to set its own fuel economy and emissions regulations, as well as the rights of other states to choose to follow California rules. Lawsuits were filed over that decision, too.

Governments around the world have steadily raised automotive fuel economy requirements for the past couple decades, causing automakers to look for improvements in a variety of ways, including from lubricants. The biggest result for the lubricant industry has been a shift to lighter viscosity grades for engine oils.

Emissions standards have also become increasingly stringent, leading first to adoption of a variety of control technologies that set new requirements on engine oil formulation and more recently to promotion of low emission vehicles such as electric cars. Electric vehicles are seen as a disruption to the lubricant industry because they do not use engine oil and because they create new performance requirements for the lubricants and fluids they do require.