A man wearing a mask rides a bicycle amid heavy smog in Hangzhou, East China's Zhejiang Province on December 7. Photo: IC

As well as North China, the Yangtze River Delta has also been suffering from heavy pollution this month, and experts said Sunday that China will not see an improvement unless it reduces its coal consumption.

Nanjing, capital city of East China's Jiangsu Province, saw its density of particulate matter smaller than 2.5 micrometers (PM 2.5) reach 411 micrograms per cubic meter on December 5.

In Shanghai it reached 602 micrograms per cubic meter on December 6, much higher than the national standard, which sets an ideal limit of 75 micrograms per cubic meter, news portal ibtimes.com.cn reported earlier this month.

Yu Yanshan, a director at the National Energy Administration, attributed the high pollution readings to consumption of coal, news agency China News Service reported Saturday.

Yu said that on average, the Yangtze River Delta consumes 10,000 tons of coal per square kilometer each year, leading to the poor air quality, according to the report.

The Yangtze River Delta, including cities in East China's Jiangsu, Zhejiang and Shanghai, is an area with heavy manufacturing and industrial activity, the report noted.

In Jiangsu, 13 cities have seen heavy pollution this winter. Jiangsu ranks highest in China in terms of thermal power generation and cement production, and the province also has the second-largest steel output in China, the report said, noting that the three industries require heavy use of coal.

The high level of coal consumption is not just a regional but a national problem for China, Lin Boqiang, director of the China Center for Energy Economics Research at Xiamen University, told the Global Times Sunday.

China consumed 3.78 billion tons of coal in 2012, with coal accounting for 68 percent of the country's energy consumption, so it is impossible for China to avoid smog, Lin said.

Upgrading the quality of petrol could help, Lin said, but reducing coal consumption is more important.

"Blue sky will be less rare if we can reduce the proportion of coal in energy consumption to 40 percent," Lin said, "but even a drop of 1 percent is extremely hard for this country."

Coal accounts for an average of 29 percent of global energy consumption, but the ratio of 68 percent in China is much higher, Yu said, according to the report.

He noted that increased use of natural gas should be considered.

Natural gas is a good substitute for coal, but at most it could take the place of 5 percent of coal consumption in the next five years, because China does not have rich reserves of natural gas, Lin said.

"We have to face the fact that solving the problem of pollution will take a long time," Lin said.

Huang Wei, a campaigner at environmental group Greenpeace, said China should reduce its coal consumption and accept a slower pace of economic growth.

The country is starting to take action about smog in East China but coal power plants are still being built in the western part of China, Huang told the Global Times Sunday.

Since 2011, the country's total installed capacity at coal power plants has risen by more than 650 gigawatts, or 86 percent, according to an article posted on the Greenpeace website on December 19.

China should not simply move the pollution from the east to the west, Huang said, noting that the government should set a clear goal and schedule to adjust the structure of energy consumption.

Beijing, Tianjin and North China's Hebei Province have set a good example for others by jointly releasing an air pollution solution plan, Huang said, noting that the Yangtze River Delta should also work out a plan for the whole region.

In addition to regulations set by the government, the public and NGOs can help in supervising pollution through information disclosure, Huang said.