California air quality regulators once hoped that battery-powered, zero-emission cars would lead the charge for cleaner air in the state, but today they are shifting their allegiance to more commercially viable cars that produce some emissions. In 1990, the California Air Resources Board mandated that 10 percent of all vehicles sold in the state by 2003 be pure zero-emission vehicles (ZEVs). Faced with market realities, the board is proposing a plan today that would require 2 percent ZEVs, 2 percent fuel-cell cars and hybrids that run on both electricity and gasoline, and 6 percent clean gasoline cars, saving the auto industry as much as $400 million. Time magazine this week has a lovey-dovey feature on two hybrid cars, the Honda Insight and Toyota Prius.