The US state of California has introduced the country's strictest regulations aimed at reducing the amount of pollution generated by diesel-consuming vehicles, it has been reported.
Under the new measures, which come into force in 2011, truck drivers have to refit older polluting vehicles or replace them completely, the state Air Resources Board ruled.
Diesel fuel pollution constitutes one-third of California's pollution levels.
Chair of the board Mary Nichols explained: "This is an industry that has an enormous impact on people's lives. This regulation will save more than 9,000 lives and reduce the toxic emissions that cause cancer and birth defects."
California has implemented several measures to improve the quality of its air, including a restriction on the burning of wood, log fires or stoves.
The system was enforced last month following a particularly polluting forest fire season.