BEIJING -- China will introduce stricter environmental standards for automobiles in a bid to cut pollutants in vehicle exhaust by an average of 50% a year.

Chinese and foreign automakers will need to introduce the latest clean-driving technologies and take other steps to meet the new standards.

China's auto market, already the world's biggest, is still growing.

The National VI emissions standard will cover major cities beginning next year. It is equivalent to the Euro 6, the world's strictest emissions controls, introduced in 2015 throughout Europe.

The move is aimed at significantly reducing the amount of pollutants, such as nitrogen oxide and particulate matter.

China's Ministry of Environmental Protection and other government bodies hope to have the plan's details worked out by the end of this year.

The tougher standard will first cover major cities such as Beijing and Shanghai before spreading to other areas in stages, starting in 2018.

The National VI standard was originally scheduled to be introduced around 2020.

In addition, Beijing plans to introduce the National V vehicle emission standard -- equal to the Euro 5 standard -- in farming villages and elsewhere in the first half of 2017.

Furthermore, the ministry is studying California's zero emission vehicle program. The ministry around 2020 will likely introduce a similar system, which requires carmakers to sell a certain number of electric vehicles and plug-in hybrids.

Separately, the government plans to raise the fuel efficiency target level to 20km per liter of gas, 40% tougher than the current level, by 2020. This means automakers will have to ensure that the fuel efficiency of all the cars they have on China's roads averages out to 20km per liter. To meet the target, automakers will have to sell more electric and compact cars.

Chinese automakers are growing concerned with the ever-stricter standards. "If the new emissions standards are introduced in earnest," said an official of the China Association of Automobile Manufacturers, half of the country's carmakers, many of which lack advanced environmental technology, could go out of business.

China's new car sales came to 24.59 million units in 2015, the seventh year in a row in which China led the world. Chinese drivers in 2015 bought 40% more cars than their U.S. counterparts and five times more than Japanese did.

According to estimates, there are 160 million cars on China's roads.