(Yicai Global) May 6 --  Shanghai, China's most populous city, plans to tighten regulation over car emission standards starting July 1.

Any new light-duty gas and diesel vehicles must satisfy the China 6b standards to be registered locally from that date onwards, the Information Office of Shanghai said in a statement today. Other vehicles will need to abide by the less strict China 6a rules.

The rollout of the new China 6 standards nationwide is set to take place over two phases. The China 6a standards for licensing and registration are due to be fully implemented across the country from July 1, 2020. The second stage, China 6b, is set to be in place three years later.

Shanghai, alongside Beijing, Tianjin and Hebei in the north and the southern province of Guangdong, have all pledged to bring in the new standards ahead of the countrywide rollout. Beijing plans to introduce 6b standards for buses and sanitary vehicles on July 1 and all other vehicles from January 2020.

The China 6b standards are even tougher than those under European equivalent Euro 6. Under Euro 6 standards, carbon monoxide emissions cannot exceed one gram, nitrogen oxide emissions cannot exceed 0.06 grams and particulate matter emissions cannot exceed 0.05 grams. Under China 6b, those figures become 0.5 grams, 0.035 grams and 0.03 grams.

Editor: James Boynton