An interministerial committee on the environment is due to approve a far-reaching plan to reduce automobile pollution next week - but key elements of the plan are threatened by a lack of funding and arguments over jurisdiction.

The plan aims to encourage the use of cars that consume less fuel and emit less pollution by altering the way vehicle taxes and fees are structured in order to make purchasing such vehicles more attractive. Currently, taxes are determined mainly by engine size; under the new plan, a vehicle's fuel consumption and emission levels would also affect the amount of tax.

The committee also plans to ban trucks from using main roads during rush hour.