According to official figures, the air quality of Beijing has improved dramatically since the beginning of its "war on pollution" that the government launched seven years ago.
The average concentration of PM2.5 in the city in 2019 - the most toxic small particles and a primary air pollution measure - plunged to its lowest level since its integrated air quality monitoring campaign began in 2013.
According to the municipal ecology and environment office, the average concentration of 42 micrograms per cubic meter in 2019 was 53 percent lower than the figure of 89.5 in 2013.
The average PM10 particulate matter and nitrogen dioxide concentrations are 68 and 37 micrograms per cubic meter, both in line with national goals.
While some levels of pollution still far surpass international standards, the rapid progress of the Chinese capital has been praised by the United Nations as an indicator of how fast things can be turned around.
In a report in March last year, Joyce Msuya, deputy executive director of the UN Environment Program, wrote that "no other city or area on the planet has accomplished such a feat."
Based on emission data from 1998 to 2017, the UN report concluded that the three most effective steps were the restrictions on coal-fired boilers, the use of cleaner fuels in residential industries, and increased industrial controls.
Ma Jun, director of the Beijing-based non-government organization Institute of Public and Environmental Affairs, said the change was the product of policies such as coal combustion controls, vehicle emission controls, cooperation with surrounding areas and better reliability of data.
In 2013, China launched its "war on pollution," with President Xi Jinping naming it as one of the three major challenges facing the country in 2017.
The municipal authorities in Beijing have closed all coal-fired plants since the start of the anti-pollution campaign and urged people to avoid using coal-fired boilers in favor of natural gas and electricity in winter.
Although this strategy faced a challenge in the winter of 2017-18 when gas shortages left people without heating in many cities in northern China, the amount of coal burned in the capital itself has dropped significantly from a peak of around 30 million tons in 2005 to 4 million tons in 2018, according to the Beijing Environment Office.
In 2018, the country's national average concentration of PM2.5 was 39 micrograms per cubic meter, down 9.3 percent from the previous year, according to estimates from the central government. China's air quality was rated as "good" for 79.3 percent of the time across 338 major cities.
