China is continuing to increase both fuel standards and efficiency. Beijing was the first city to begin investing in cleaner fuel, and Shanghai raised the bar over the weekend.

The changing fuel ratings board. That means new oil standards are applied.

Under the new standard, all the gas stations have to downgrade fuel ratings, and newly produced purer oil will be on sale soon.

But for companies, it takes money to upgrade the production system.

"We spent 8.5 billion yuan to upgrade the oil production, increase to 2.6 million tones from 1 million." Yang Guoliang, Sr. Engineer, Sinopec Shanghai Petrochemical said.

Critics are concerned whether the extra cost will be passed on to consumers.

"It's not reasonable that companies pass too much cost on to consumers. Short-term price increase to pass on cost pressure is appropriate, but in a long run, companies should digest the pressure during distribution." Han Wenke, Dir. of Energy Res. Inst. National Dev't & Ref. Commission said.

The serious air pollution in China triggers public outcries over fuel emission. China is planning to revise up a nationwide oil standard by the start of 2014.