The act requires more stringent emissions testing for vehicles in these areas.

The benefits of modest but increasingly stringent emissions reductions would exceed the costs at first, according to his analysis.

Passenger car versions had the same engines, but all with 2 hp less due to more stringent emissions controls.

At the same time, engines were being progressively detuned to comply with increasingly stringent emissions regulations.

Rather than fighting the Administration for less stringent emissions standards, the auto industry has allied itself with environmentalists in demanding cleaner gasoline.

Class "0" (generally, cars less than 9 years old and meeting more stringent emissions requirements) are exempt from the Hoy no Circula program.

The new Toyoace also met new more stringent emissions and noise standards introduced for 1979.

By 1992, we shall have the more stringent California-like emissions controls on cars in New Jersey.

The least stringent emissions standard in California.

They were withdrawn from those markets largely because of more stringent emissions requirements.