I live in Brussels. I walk/run throughout the city every day. There's tents next to the rail station, there's tents next to large supermarkets, next to parks... everywhere. 3 years ago that was not the case. Metro stations are also overwhelmed with people passed out on heroin or whatever drugs they use. The difference is more than noticeable.

I visited Frankfurt just 1 month ago and was shocked to see the situation being even worse.

I believe a lot of it is a post-effect of covid where some people fell through the craks and now are just lost to drugs or other addictions.