New pollution regulations that are the equivalent of taking 177 million cars off the road have been announced in the US.
President Barack Obama has unveiled America’s first-ever nationwide standards to cut vehicle emissions, which will force US car makers to produce more efficient vehicles by 2016.
The scheme, which is due to start in 2012, is projected to save 1.8 billion barrels of oil and reduce greenhouse gas emissions by 900 metric tonnes.
"For the first time in history we have set in motion a national policy aimed at increasing gas mileage and decreasing greenhouse gas pollution for all new trucks and cars sold in the United States," Obama told state governors.
The new rules will push fleet average fuel consumption for US vehicles to 35.5mpg (42.6mpg in UK) by 2016 and most passenger cars must reach 39mpg (46.8mpg in UK). For the latest 2009 models, the fleet average for US vehicles is 25mpg (30mpg in UK).
US car makers welcomed the nationwide efficiency standard.
"Energy security and climate change are national priorities that require federal leadership and the president's direction makes sense for the country and the industry," said GM CEO Fritz Henderson, saying the standardisation "will benefit consumers across America."