SHANGHAI (REUTERS) - China's cabinet has issued a timetable for oil companies to deliver cleaner fuel nationwide beginning this year, the Xinhua news agency reported, but the new standards won't become mandatory for four years despite rising public anger over choking air pollution.

Thick smog has blanketed many Chinese cities in recent weeks and auto emissions are among the major contributors to the pollution.

A new standard will be issued for automobile petrol that caps sulfur content within 10 parts per million (ppm) before the end of the year, with a grace period extending to the end of 2017, Xinhua said after an executive meeting of the State Council that was chaired by Premier Wen Jiabao.

Beijing is so far the only city in China to have adopted such a standard, equal to Europe's Euro V, it said in a report late on Wednesday.

Excessive pollution levels have prompted the Beijing government to roll out a series of temporary emergency measures, such as shutting down 103 heavily polluting factories and taking 30 per cent of government vehicles off roads.

Despite those steps, the capital's air has remained hazardous on many days.

A new standard for automobile diesel that would limit sulfur content to within 10 ppm will come before June this year but will also have the same four-year grace period, Xinhua said.

The General Administration of Quality Supervision, Inspection and Quarantine and the Standardization Administration would soon issue a transitional standard for automobile diesel with sulphuric content within 50 ppm that would expire at the end of 2014.

Cleaner fuel may also mean higher prices. The cabinet said prices should be "fixed properly" and subsidies should be given to disadvantaged people and non-profit organisations.

Analysts say foot dragging by China's highly influential state oil companies, which will need to upgrade refining equipment to meet the new standards, has contributed to the pollution problem.