LOS ANGELES, SEPT. 28 -- The California Air Resources Board today approved the world's most ambitious smog-control plan, requiring production of electric and other low-polluting vehicles that would reduce emissions to a fraction of current federal standards.

In a series of last-minute compromises that solidified industry support for the plan, the board slightly adjusted some deadlines for cleaner car production. It also dropped a requirement that oil companies market specific amounts of cleaner fuels, such as compressed natural gas, as long as they make such fuels available to drivers who want them.

The vote means that, within 10 years, all new cars sold in the state will be what the board calls "ultra-clean" vehicles, probably including "flex-fuel" cars running on a mixture of methanol and gasoline, cars burning ultra-clean gasoline with new electrically heated catalytic converters, compressed natural gas cars, propane cars and electric cars.

The board became the first government body in the world to require mass production of electric vehicles, which must represent 2 percent of all new car sales here in 1998 and increase to 10 percent of California's estimated 2 million annual car sales by 2003.

Other states are studying similar standards, which are much stricter than even the new federal clean-air standards being debated in a congressional conference committee. "This body has taken the leadership globally in the treatment of air pollution," said board member Brian P. Bilbray, a San Diego County supervisor.

California, particularly the Los Angeles basin, has the most polluted air in the country. Although the area has the nation's strictest emission standards, motor vehicles still produce about 53 percent of all smog-forming hydrocarbons and nitrogen oxides and about 82 percent of all carbon monoxide.

The board's plan, which has the force of law, is expected to reduce daily hydrocarbon emissions by 28 percent, nitrogen oxide by 18 percent and carbon monoxide by 8 percent by the year 2010.

Bilbray, while voting with the other board members 8 to 0 for the unprecedented plan, complained of "intense lobbying" from special interests and legislators in Sacramento and Washington concerned about increased costs to motorists and harm to the state's economy.

He said he was willing to support the last-minute adjustments in the plan since the board could toughen its requirements at any time, if needed.

Bill Ott, a spokesman for General Motors, said 14 oil companies and the three major automakers are pursuing a joint research project to identify types of engines and fuels that could meet the board's goals quickly and cheaply. "We don't have the technology to meet the standards now," he said. "We don't have any miracles on the shelf."

But Raymond D. Buttacavoli, an emissions-control expert for General Motors, said the joint study was an improvement from the days when "the automobile companies and the oil companies were bashing each other over the head."

Industry concern about finding customers for the new vehicles and fuels appeared somewhat eased by the board's amendments today. "It's a plan that will help us develop what is needed," said Douglas Henderson, executive director of the Western States Petroleum Association. "We can live with it," said Sam Leonard, director of automotive emission controls for GM.

The California plan phases in progressively cleaner vehicles. At least 10 percent of new vehicles in 1994 to 1996 would have to meet a standard of 0.125 grams per mile of hydrocarbons, compared with the current federal standard of 0.41. Under proposed federal law, a na-tional standard of 0.25 would be phased in between 1993 and 1998.

Under the California plan, the initial group of "transition" vehicles, probably those used in business automobile fleets, would begin being replaced in 1997 with "low-emission vehicles" (LEVs) emitting only .075 gpm of hydrocarbons and 0.2 gpm of nitrogen oxide.

In 1997, 25 percent of new cars sold in California would have to be LEVs, with an increase of 25 percent each year until a maximum of 96 percent of all new cars is reached in 2000, with the remaining 4 percent composed of even cleaner cars whose percentage continues to increase toward 2003.

Automobile executives said they are concerned about consumer resistance to increased costs of the new equipment. Car buyers already pay an extra $100 for testing of pollution equipment on GM cars sold here. Board members said they worried about new cars not having the speed and acceleration demanded by freeway driving.

But Bill Sessa, spokesman for the board, said he had recently driven prototypes of all sorts of ultra-clean vehicles and found that they accelerated as well as gasoline-powered cars. Bilbray suggested that cars burning cleaner fuels bear markings that would allow them special parking and carpool lane privileges.