The situation in China is actually even worse. There are environmental regulations, but enforcement is easily evaded through bribes or CCP connections.
Every so often there is a disaster that forces the government to start a much-publicized campaign. A few of the worst or least connected offenders get punished and then it's back to business as usual.
So really, if you're just anybody and start polluting, you'll quickly be stopped. Meanwhile the state-owned steel mill next door has been blasting out unfiltered coal exhaust for decades.
Look for a broad-strokes summary of environmental laws in China [0]. Note the following paragraph:
> The standards detailed in the action plan focus on several harmful substances, including particulate matter (PM2.5 and PM10), sulfur dioxide (SO2), nitrogen oxides (NOx), and volatile organic compounds (VOCs). Each of these pollutants has defined permissible levels, which are critical in guiding both regulatory authorities and industries in their compliance efforts. Over the years, the Chinese government has intensified its efforts to monitor real-time air quality and ensure adherence to these standards
Now try to reconcile this with the actual air quality [1] [2]. Note that September is far from the peak, when it gets cold and dark the air quality in many megacities becomes off-the-charts toxic.
This leaves two possibilities: either the state is too weak or too corrupt to enforce these laws. Since the PRC is far from weak and its organs are very powerful, this only leaves one possibility.
So really, if you're just anybody and start polluting, you'll quickly be stopped. Meanwhile the state-owned steel mill next door has been blasting out unfiltered coal exhaust for decades.