Photo taken on June 11, 2015 shows a turret of the Forbidden City in Beijing, capital of China. Beijing witnessed fine weather on Thursday after days of thundershower. (Xinhua/Li Xin)
After a heavenly week of "unprecedented" blue skies, gray haze greeted Beijing commuters on Monday morning. Some people, like Chen Shan, welcomed the return of old friend smog, as it was a sign the city was back to "normal".
"The more cloudy the sky, the more we should remember its blue times," Chen wrote on Weibo, the Twitter-like website, alongside two photos of the view from his office, one with a clear blue sky, and the other gloomily, hazy and gray.
The dreamy sky was a hot topic across social media, and even made headlines. Pictures of landmarks in Beijing framed by a clear blue sky and white clouds went viral.
According to the Beijing Municipal Environmental Protection Bureau, the city's average density of PM2.5, harmful particles that are small enough to enter the bloodstream, dropped to a record low of 5 micrograms per square meter last Friday, a decrease of 19 percent compared with the same period last year.
Chen Tian, head of the bureau, attributed the remarkable air quality to a reduction of coal burning and less construction.
The bureau said Beijing's air quality had improved in the last four months due to air pollution control efforts and favorable weather conditions. The number of severe pollution days has dropped by 42 percent year on year.
Zhang Qian, a businessman who frequently travels between northwest China's Urumqi and Beijing, limits the time he spends outside while he is in Beijing. But this weekend, he pulled on his hiking boots and went for a walk.
"I never expected such excellent weather in Beijing and I didn't want to waste it by staying in the hotel, like I normally do," Zhang said. "If the sky in Beijing stays blue like this, I will enjoy my job even more."
Measures to control pollution prior to and during big political events, such as the "two sessions" in March and the Asia-Pacific Economic Cooperation (APEC) meetings last November, were successful.
Chinese netizens even coined the phrase "APEC Blue" to describe the city's clear skies at the time.
Beijing government vowed to bring back APEC Blue by scaling up air quality control, a ban on outdoor barbecues is its latest move.
Last year, Beijing reduced its coal consumption by 2.8 million tonnes. In March, two coal-fuel power plants were shut down, and 200,000 vehicles and more than 300 polluting factories will also be phased out this year.
Air pollution has been identified as a major obstacle to Beijing's bid for the 2022 Winter Olympic Games.
The Chinese capital issued a five-year plan on its environment, vowing to clean its air by cutting PM 2.5 density by 20 percent by 2017, with an investment of 130 billion U.S. dollars in the field.
"We are confident that we can have fresh air in Beijing, not only by significantly improving the air quality, but also by paving a new, healthier and greener path for the city and the surrounding region's development for years to come," said Wang Anshun, Beijing mayor and president of the Beijing 2022 Bid Committee.
