How does china implement massive facial recognition for their surveillance?

Hi, I've been seeing videos online about the "social credit" and jay walkers get a ticket automatically in cities like shenzen. China has a billion people, how do they implement face recognition / body language detection at a massive scale? How do they avoid false positives? considering the camera angles, dust, etc



Please let me know if this post is against the sub rules, I'm just a curious mind haha

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