Do you know the approximate year when those tables were introduced in China? They seem to have gotten out of China only in the past 10 years or so.
I'll ask around. I have seen pictures that are like 50years or so old. I can ask someone and get a more definitive answer. Some of my favourite photos are late 80s/early90s outdoor tables with many people playing.
EDIT:
So the 50 years or so is right to some degree, but this would not have been pool. Most likely English billiards brought across by the British.
Wang Dashi, who was the director of Beijing Haiyan Billiard Table Factory in 1984 manufactured the first international standard snooker table. After that, he began the research and manufacture of American pool table in 1985. Lacking proper reference, he manufactured his imaginary “American pool table,” derived from snooker table structure and size of carom table. It was considered a miniature snooker table. Consequently, there came into being a new billiard discipline, and that was playing American pool games on a small-sized snooker table. Which is where the table comes from, and lines up with the outdoor pool table photos I have seen
If I find those photos, I will post them because they are incredibly bad ass!
DOUBLE EDIT:
I have pulled an all-nighter at work... So for some reason my melted brain put 50 years ago at 1950s....

So, I was right in my initial comments, they are about 50years old... But billiards has been played in China since the early 1900s, brought across by the British.