Producing and using biodiesel, a fuel derived from cultivated rapeseed, causes 35 percent less air pollution per gallon than does producing and using regular diesel fuel. The government plans to reduce diesel-related air pollution over the next decade by 25 percent, so replacing regular diesel with biodiesel would seem to be the obvious solution. Unfortunately, the greatest possible production of biodiesel would amount to only one percent of all diesel fuel to be produced during the next 15 years.