Wow you can get lost in there! Some interesting and poignant stuff thanksI've spent much time over the last four years photographing drug addicts, pushers and prostitutes, up-close and very personal.
I know nearly all of them in my city in northern Italy. I can go places even the police are wary to go, and I have total freedom to photograph anything. A very small selection of those photos can be seen on my website link
In the time I've spent photographing them, I've seen them chase away the police a number of times (6 armed officers ran away from them on one occasion) and also several raids by the military (the armed soldiers ran away from them too).
Many of them live rough and haven't washed for years. They smell revolting, and many have lice. They sh1t on the grass right next to where they smoke or inject, so I can't see any of the above suggestions about using smelly substances working.
They don't seem to care about surveillance cameras, not even the official police cameras, and the police here, as I imagine in many other cities and countries have just given up trying. Even during Covid they don't use masks and they don't respect the curfew or any other regulations. They are a law unto themselves.
Stabbings here are frequent, which confirms advice given earlier in this thread, don't approach them. They will also threaten to stab with used syringe needles.
Tomorrow (Monday) I'll go and ask them if there is anything that would put them off frequenting an area. If I get any useful suggestions I'll come back and post them tomorrow evening.