Canada's federal government will tighten regulations on sport utility vehicles by changing their classification from trucks to cars to force manufacturers to abide by their tighter emissions laws, reducing pollution from the relatively fuel-inefficient models.

The move is part of an overhaul of Canadian maximum emission levels for oxides of nitrogen, which will see the ceilings for cars reduced from 0.3 grams per mile to 0.07 grams per mile. Importantly, this new reduced maximum will also apply to SUVs, down from the truck-standard of 1.53 grams per mile that currently applies.

"Vehicles are a major source of the air pollutants that contribute to the formation of smog," said Environment Minister David Anderson.

"SUV's have evaded the regulations that were put in place for passenger vehicles. The smog contribution from a new SUV will drop dramatically," he told the Montreal Gazette.

The new regulation will come into effect in September of 2003 for 2004 models, matching standards applying in the United States.

This latest move is part of the Canadian government's on-going campaign to reduce smog and climate change-causing pollutants emitted into the air and also to prevent Canada from becoming a dumping ground for unacceptable technology from the US.