Cao Xianghong has been director of the National Petroleum Products and Lubricants Standardization Technical Committee for more than 10 years. He spoke to China Daily about the cost of upgrading the gasoline standard from phase 4 to phase 5.

The main difference between the two standards lies in the sulfur content allowed in gasoline and diesel - 50 micrograms per gram for phase 4 and 10 mcg per gram for phase 5.

"The increased cost will be around 200 yuan ($32.70) per metric ton, two-thirds of which will result from the loss of Methylcyclopentadienyl Manganese Tricarbonyl, or MMT," said Cao.