As the leader of China's ruling Chinese Communist Party pledged to slash the country's carbon emissions and boost consumption of non-fossil fuels, the nation's capital issued the first smog alert of the winter, warning people to stay indoors and ordering factories to halt production.
As President Xi Jinping arrived in Paris at the start of a long-awaited climate change summit, Beijing municipal authorities issued an orange smog warning forcing industrial facilities to reduce or shut down production, official media reported.
"The municipal environment watchdogs have reinforced checks of discharge from coal-fired plants, outdoor barbecues and burning," state-run Xinhua news agency reported.
Under an orange alert, construction sites will be ordered to halt the transportation of materials and waste, while heavy-duty trucks are ordered off the roads, it said.
China's smog has repeatedly brought large swathes of the country to a standstill, particularly in the north, forcing airports to cancel thousands of flights, requiring schools to close, and reducing visibility on city streets.
The U.S. Embassy in Beijing, which monitors air pollution unofficially, tweeted that PM2.5 particulate matter concentrations were off the scale, measuring 589 on Monday, nearly 30 times the level considered safe by the World Health Organization.
"Humidity and a lack of wind ... mean the smog will linger for another two days, before a cold front arrives on Wednesday," Xinhua reported.
Beijing resident Xu Yonghai said such alerts are no longer surprising to local people.
"We have had these sorts of conditions every winter for the past few years now," Xu said. "The smog has been very serious in recent days, but it is no longer out of the ordinary."
"We will have to wait for a strong wind to blow, or for snowy weather, before we can breathe fresh air again," he said.
While debate over the causes of north China's "airpocalypse" continues to rage, Xu said many in Beijing associate the poor air quality with the ubiquitous coal-fired central heating furnaces across the city.
"Every winter, because we need to stay warm, we have to breathe in toxic gases; it's horrible," Xu said.
He said the government has shown the capacity to clean up the skies over Beijing when it wants to.
"The Chinese Communist Party is totally capable of cleaning up this pollution; look at the deep blue skies we had in Beijing during the APEC summit [in October 2014]," he said.
"But there is a very big price to pay; they had to turn off all the factories in Beijing and northern China."
In Paris, Xi told the climate change conference that China wants to "strive to achieve" significant reductions in CO2 emissions within two decades.
"China pledges to peak CO2 emissions by around 2030, and [to] strive to achieve it as soon as possible," Xi said. "And by 2030, [to] reduce CO2 emissions per unit of GDP by 60-65 percent over the 2005 level."
"[China will also] raise the share of non-fossil fuels in primary energy consumption to about 20 percent," he said.
He added: "All countries, and developed countries in particular, should assume more shared responsibility for win-win outcomes."
Hong Kong-based sustainability expert Albert Lai, who heads an independent public policy think-tank, said he has low expectations for the Paris climate talks, however.
"It's going to be extremely difficult in political terms to reach a speedy agreement," Lai told RFA ahead of the talks. "China and the U.S. are basically in disagreement, and only the EU is really in favor of a legally binding agreement on cutting emissions."
"The crucial thing is that the approach has already shifted to a bottom-up approach in which countries put forward their own voluntary pledges to reduce emissions," he said.
Lai said government transparency is crucial to cutting emissions. "If they can test [each country's] emissions every five years ... then that would be the most favorable outcome."
He said local communities and organizations also need to be actively involved in cutting carbon emissions, however.
"We won't be able to reach these emissions targets just by relying on governments," Lai warned.
Around 600 million people are affected by air pollution and smog days that plague northern China, according to a July report from China's State Development and Reform Commission.
And a recent report by the American National Academy of Sciences found that residents of northern China could be losing five years of life expectancy compared with those in the south, which until recently has enjoyed better air quality.
Reported by Gao Shan for RFA's Mandarin Service, and by Dai Weisen for the Cantonese Service. Translated and written in English by Luisetta Mudie.