While most areas in North China were shrouded by heavy smog recently, residents in Datong, Shanxi province, were enjoying bright blue skies.

For the fourth year in a row, Datong's air quality was ranked the best in Shanxi in 2016.

According to statistics from the provincial environmental department, Datong met national air quality standards for 314 days last year, far surpassing the average level in the province of 249 days.

A heavy consumer of coal, Datong was ranked the third-worst Chinese city for air pollution out of 113 in 2005.

To change that situation, the government has made great efforts to protect the natural environment and reform the city's use of energy.

Statistics suggests that the amount of green coverage in Datong had reached 40.96 percent by the end of 2016.

"The government will spend another 480 million yuan ($69.89 million) on wetland construction and sewage disposal this year," said Zhao Xiaoning, head of Datong’s environmental protection bureau.

Coal, as the major source of pollution in the city, is gradually being replaced by clean energy, such as gas and electricity. So far, electric heating covers 99.7 percent of households in the city and gas users have reached 684,000, with the coverage ratio at 98.7 percent.