• Shell's comments push back against the EPA plan to revoke California's power to impose emissions standards that are tougher than the federal rules, calling it a "step in the wrong direction."
• California has a special authority under the Clean Air Act to set separate tailpipe standards that roughly a dozen other states also follow.

Where it stands: California is fighting to keep its power to maintain tougher rules even if the federal standards are rolled back. But automakers fear that would create a messy patchwork and want California and the EPA to strike a deal that preserves a single nationwide set of rules.

The intrigue: The oil giant's views signal how the Trump administration's dismantling of Obama-era climate rules puts the White House to the right of even some big fossil fuel companies.

• However, Shell's climate message is absent from more detailed comments filed by the American Petroleum Institute, the powerful oil-and-gas lobbying group.

The big picture: The fight over Obama-era auto rules — a pillar of the former president's climate policy — is pretty messy.

• While big automakers say they don't support freezing the standards in place, they have lobbied for some kind of relaxation of the Obama mandates, calling them too stringent.
• Shell, for its part, doesn't weigh in what the standards should be, but instead simply agrees with the auto lobby that they should not be frozen.