"The air quality in Beijing-Tianjin-Hebei area in North China is improving, and Beijing has seen more obvious changes," Bai Qiuyong, chief at the Department of Ecological and Environmental Monitoring of Chinese Ministry of Ecology and Environment (MEE) said at a press conference on Wednesday.
Bai said that the air quality index (AQI) often fluctuates, indicating that air quality is affected by weather patterns.
"Improving air quality will be difficult, complex and take a long time, and we vow to win the battle to guard the blue sky," he said.
Beijing had 227 days of good or moderate AQI in 2018, the MEE said in January.
The AQI was good or moderate 79.3 percent of the time last year in 338 key cities around China, a year-on-year increase of 1.3 percentage points, according to the 2018 China Ecology and Environment situation public report released on Wednesday by the MEE.
Those cities saw a combined 1,899 days of severe pollution, 412 fewer days than in 2017, said the report.
However, the cities also saw a combined total of 822 days of extreme pollution, which was 20 days more than 2017.
PM2.5 readings in 169 cities registered a 9.4 percent year-on-year decrease.
The annual report also said that the quality of China's surface water, coastal water and ecological environment has also improved.
MEE spokesperson Liu Youbin said that large scale illegal use of ozone-destroying CFC-11 has not been found in China, following reports that an alleged mysterious rise of CFC-11 had been detected in North China.
He said that scientists are welcome to conduct deeper research into the rise of CFC-11.