BEIJING (Reuters) - China will replace four coal-burning heating plants in the capital Beijing with natural gas fired ones by the end of next year as it steps up efforts to clean up pollution, the official Xinhua news agency reported on Saturday.

The report, citing the city's Municipal Commission of Development and Reform, said the four plants and some 40 other related projects would cost around 48 billion yuan (S$9.8 billion)and cut sulphur dioxide emissions by 10,000 tonnes. It did not detail the related projects.

The plan is the latest step by authorities to deal with a persistent smog crisis in China's big cities that is fuelling public anger. The capital has been shrouded in thick hazardous smog for several days during the ongoing seven-day national holiday.

China has been under pressure to tackle air pollution to douse potential unrest as an increasingly affluent urban populace turns against a growth-at-all-costs economic model that has besmirched much of China's air, water and soil.

Last month the government announced plans to slash coal consumption and close polluting mills, factories and smelters, though experts said implementing the targets would be a major challenge.

The new plants will replace four coal-fired ones that provide heating for homes in the city's central urban area as well as generating electricity, Xinhua said.

The four burned 9.2 million tonnes of coal in 2012, or 40 per cent of the 23 million tonnes the city consumed in the year, it added.