The amount of pollutants discharged from vehicles has reduced significantly after cleaner fuels meeting the China III standard were introduced in Shenzhen on April 16, the environmental watchdog said Thursday.

A survey of 2,042 vehicles by the municipal environmental protection bureau between April 16 and May 15 showed that the level of carbon monoxide and other major pollutants discharged by the vehicles had reduced by nearly 15 percent compared with the period from March 16 to April 15.

"The level of carbon monoxide is down by 12 percent in Futian District, 14 percent in Nanshan and 19 percent in Luohu," the report said.

In terms of total hydro-carbon emissions, the three districts have seen an average decline of 24 percent.

"The number of complaints from the public on air pollution caused by vehicle exhaust emissions also dropped from 216 in March to 195 between April 16 and May 15," said Shen Rong, a spokesperson for the bureau.

According to the bureau, new vehicles failing to meet the China III standard will not be registered with the local traffic authorities from July 1.

Vehicle retailers said the new regulation will not affect their sales, as more than 90 percent of the cars in the market meet the new standard. China III standard fuels, similar to the Euro III standard, are expected to reduce the amount of vehicular emissions in Shenzhen by about 44,200 tons annually.

Car exhaust has become a major source of pollution in the city. The number of vehicles registered in Shenzhen reaching 1 million in March.

Editor: Yan