This is Hainan

Haikou, Hainan province remained in first place on two air quality lists released by the Ministry of Ecology and Environment. One list was for December 2018, while the other was for the entire year of 2018.

A total of 169 major cities were included in the lists.

The 10 cities with the best air quality on the December 2018 list were Haikou, Zhoushan, Fuzhou, Huizhou, Huangshan, Xiamen, Nanning, Shenzhen, Guiyang and Kunming.

The top 10 cities on the list for the whole of 2018 were Haikou, Huangshan, Zhoushan, Lhasa, Lishui, Shenzhen, Xiamen, Fuzhou, Huizhou and Taizhou. However, Hebei province, China's biggest steel-producing region, was the location of five of the country's 10 smoggiest cities in 2018, including Shijiazhuang, Xingtai and Tangshan.

Blue skies were present in 79.3 percent of all days in 2018, up 1.3 percentage points from 2017, the Ministry said. "Blue skies" refers to days when the average air quality index is lower than 100.

According to an official from the Haikou municipal ecology and environmental protection bureau, in 2018 the city improved preventative measures against flowing dust pollution, exercised strict control over mobile sources of pollution, effectively managed industrial air pollution, treated cooking oil fumes and raised awareness of new energy.