A blanket of humid, still air resulting in smog that is expected to shroud Beijing for at least three days triggered the capital's first ever pollution "red alert" on Tuesday as many residents ignored warnings to limit their time outdoors.
By early morning, hundreds of people, including toddlers, had packed Tiananmen Square to watch the flag-raising ceremony, according to photos by state news agency Xinhua.
State radio said some people were ignoring vehicle use restrictions, which on Tuesday banned vehicles with odd numbers at the end of the licence plate getting on the roads, though the roads were noticably quieter.
Environment Minister Chen Jining called a special meeting on Monday night to urge more supervision in Beijing and its surrounding cities including Tianjin as he increased the number of environmental inspection teams to 12, according to ThePaper.cn, a state-backed news website.
Although smog has always been a public health concern in Beijing, the government's response system has come under extra scrutiny in the past week because it came under heavy criticism for not issuing a red alert during an episode of heavy smog which exceeded hazardous levels. Chinese researchers have identified pollution as a major source of unrest around the country.
Greenpeace called the red alert "a welcome sign of a different attitude from the Beijing government".
"From repudiating PM2.5 [particulate matter with a diameter of 2.5 micrometers] to today's issuance of a red alert, in just a few years, this is a near-revolutionary change in thinking," Hu Xijin, the editor-in-chief of the influential state-run Global Times tabloid, wrote on his microblog on Tuesday.
The Beijing City Emergency Office said. "still weather, reduced cold temperatures and an increase in humidity" prompted the red alert, according to Xinhua.
A red alert means that 30 percent of vehicles will be taken off the roads, heavy vehicles will be banned, most schools will be advised to cancel classes, businesses are recommended to implement flexible working hours and all "large-scale, outdoor activities" should be stopped.
Despite this, many residents tried to circumvent the rules. State radio showed a picture on its official microblog of a policeman removing paper stuck to a vehicle's licence plate to obscure its final digit.
By late morning on Tuesday, the US embassy's monitoring station recorded an air quality index of 250, which puts air pollution levels in the "unhealthy" region.
Those who did struggle to the office posted pictures on social media of themselves wearing industrial-strength face masks.
"I feel like I'm engaged in chemical warfare," wrote one commuter.
Still, the ruling Communist Party's official People's Daily, without a hint of irony, praised China's contribution to fighting climate change in a commentary on Tuesday, written to coincide with the Paris climate talks.
"People everywhere are looking forward to China's continuous progress on the road to green development, acting as a model for the world to tackle the challenge of climate change."