LONDON - Trucks that produce high levels of pollution must pay 200 pounds (C$394) a day to drive into London under rules that came into effect Monday.
Mayor Ken Livingstone says the "low-emission zone'' will improve air quality and reduce pollution-related deaths.
But groups representing truckers claim it will be expensive to implement and offers little benefit.
The plan uses a network of cameras to monitor vehicles entering the city. Their licence plate numbers will be checked against vehicle records to see whether they meet European Union standards for exhaust emissions.
Those that do not must register and pay 200 pounds a day, or face a fine of 500 pounds (C$985).
The zone initially applies to diesel-fuelled trucks over 12 tonnes that don't meet EU standards, but will be extended to smaller vehicles -- including buses, minibuses, large vans and ambulances -- beginning this summer.
Cars and motorcycles are exempt.
London's program claims to be the world's largest low-emission zone. Similar zones exist in several European cities including Berlin and Stockholm, Sweden.
In 2003, Livingstone introduced London's congestion charge, an eight-pound toll on every car entering central London during office hours on weekdays.
The charge has been credited with cutting traffic gridlock and increasing the number of bus and bicycle journeys.
