According to a news conference held by the Lanzhou Municipal government on Thursday, the number of days with good air quality in Lanzhou reached 296 in 2019, an increase of 39 days year-on-year.

The ambient air quality composite index has been declining for seven consecutive years, and the air quality has been improving year by year. In the first five months of this year, Lanzhou had 131 days of good air quality, an increase of five days over the same period last year, or 86.2 percent.

Lanzhou is one of the first major industrial cities built since the founding of the People's Republic of China. It has been one of the cities with the most serious air pollution in China and even in the world due to the large discharge of industrial and domestic pollution sources. The geographical terrain of the city is also not conducive to the diffusion of atmospheric pollutants. In recent years, the local government has been committed to controlling pollution, resulting in continuous improvement in air quality.

While the atmospheric environment in Lanzhou continues to improve year after year, the quality of surface water in the Lanzhou section of the Yellow River and the quality of urban centralized drinking water sources have reached 100 percent.

"With all sources of pollution under supervision, the goal of controlling these sources of pollution has been achieved. In addition, while implementing quantitative assessment and network format management, Lanzhou has also introduced technical means, including satellite remote sensing and drone aerial photography, so that combined with the main aircraft defense and the auxiliary civil air defense, the costs of administrative, law enforcement and management have been greatly reduced," said Wu Weihong, deputy director of the Lanzhou Ecological Environment Bureau.