It goes beyond zoning laws. China has maybe 4 classes of businesses: small businesses (which pay small bribes to local officials instead of following the rules), bigger businesses (which are gradually pressured to play by the book, depending on their size and who they are bribing), state-owned entities (which get the rules changed if they want to do something, but generally follow whichever level of government they report to), and foreign businesses (which have to do everything by the book).
So, it's probably illegal to run a business from a street-level apartment. But they do it anyway, because the government generally just says "no harm, no foul" (and some red envelopes probably get passed around). A homeless guy can buy a box of coke (or even beer), and sell it at a bus stop, and as long as he keeps on good terms with the local powers no-one would raise an eyebrow. He wouldn't get much business, though, because there'd be a guy with more capital doing it better and cheaper 10 steps away. In the US, he'd need a hawkers permit (which is usually literally impossible), a liquor license, a business license, regular tax returns, and so on.
So, it's probably illegal to run a business from a street-level apartment. But they do it anyway, because the government generally just says "no harm, no foul" (and some red envelopes probably get passed around). A homeless guy can buy a box of coke (or even beer), and sell it at a bus stop, and as long as he keeps on good terms with the local powers no-one would raise an eyebrow. He wouldn't get much business, though, because there'd be a guy with more capital doing it better and cheaper 10 steps away. In the US, he'd need a hawkers permit (which is usually literally impossible), a liquor license, a business license, regular tax returns, and so on.