Beijing has raised its pollution warning system to the very highest level for the first time ever.
The smog that envelopes the capital city is all-too-familiar. But this time, it prompted the government to issue a "red alert," shutting down schools, construction sites, and keeping half of the city's vehicles off the roads.
Outside a children's hospital in Beijing, CBS News correspondent Seth Doane spoke to one parent concerned about his son's respiratory problems.
"He's feeling really, really bad - actually... for a few days," said father Robin Liu, who wore a mask to protect himself from the toxins in the air. Several doctors have suggested his seven-year-old's lungs ailment may be related to the smog.
But Liu said he feels the government is doing its part.
Beijing's pollution had been improving in the first 10 months of this year compared to 2014. Still, fifth-grader Jason Zhang -- who had to miss school because of the red alert -- said the situation was "so bad."
Zhang also said it was "kind of weird" that a red alert had not been issued last week when the pollution was even worse.
At that time last week, China's president was in Paris for the climate conference and his government was widely criticized for not sounding the pollution alarm.
Schools and factories are supposed to remain closed for two more days days until a cold snap comes in and -- hopefully -- pushes out the pollution.