Car firms call on Trump to keep emission limits

More than a dozen car manufacturers, including Ford, General Motors, Toyota, Honda and Volkswagen have officially asked US President Donald Trump not to relax emission limits, to avoid a fragmentation of the car market, US media reported.

Trump's administration last year proposed to roll back fuel efficiency standards introduced under former president Barack Obama, sparking warnings of a legal fight with California and other states that favor more aggressive environmental policies.

In a letter sent to the White House and revealed by the New York Times on Thursday, the firms called for a compromise between the Trump administration -- looking to support the car industry by relaxing emission limits -- and the country's most populous state.

A move to water down controls could see California and more than a dozen other states take the matter to court. Manufacturers fear a divided and complicated US car market would result, in which companies would have trouble making decisions on pricing and what cars to sell.

It is a nightmare for manufacturers who warn in the letter to the White House against "an extended period of litigation and instability."