WASHINGTON( REUTERS)-A group of 21 state attorneys-general, the District of Columbia, and several major United States cities urged the Biden administration to finalise significantly stricter vehicle emissions rules than it has proposed. The US Environmental Protection Agency( EPA) in August called for reversing the Trump-era loosening of vehicle emissions rules with a new plan to boost efficiency 10 per cent in the 2023 model year and aim for a fleet average of 52 miles per gallon( mpg) by 2026.