I expect most of us have seen these videos, or ones similar to them. You don't need to watch all of it.
It doesn't matter where or when they were taken, such scenes are to be found all over. I don't know exactly what makes these folk act like zombies, but I believe it's usually either Fentanyl or Crack Cocaine.
Fentanyl, like Cocaine or Heroin, is an expensive habit, which can cost the user anywhere between $500 and $1,500 per week (I could only find USA figures). Quite where the money comes from is anyone's guess.
I find looking at these images extremely upsetting. I also find it quite bizarre that no-one seems to care about them. They are simply left to their own devices; in their own mess. They have been abandoned.
Most of us will have, at some time or other, experienced some form of drug; whether it be Hashish, Alcohol, Tobacco, etc; but most of us can't be bothered with it, and stop. Personally I've never been interested in illegal drugs; preferring Beer or Wine to anything bought on a street corner. I also prefer to be in control of my faculties at all times.
But here is the problem. These drug users take their fix specifically to be out-of-control of their faculties. To block out whatever pain life has offered them, and live in a world of fantasy.
I believe that most of the world's Fentanyl comes from China. New synthetic opioids are being created almost daily and shipped to the USA and elsewhere in vast quantities. One figure I read said that there are an average of 37,000 deaths annually from such drugs in the USA alone. By the time I post the above, no doubt some of those in the video will have joined the statistics.
The dealers/manufacturers get rich, whilst the users get sick and die.