In the very post before the one I am replying to you called the type of housing that needed to be upgraded as 'slums'. Again, I am agreeing with you. They need to be improved. But we both know that people who live in the projects, who live in slums aren't doing it because it's an easy commute to the bank or it's quite handy for the beach, or the local restaurants are well worth a visit. They live in slums because they can't afford to live anywhere else. I'll assume that you agree with that. So...
...to upgrade a tenement you need to move all the people out while it's being done. They can't afford to live anywhere more expensive, so is there some vacant slum they can afford where you can house them until their old place has been brought up to scratch? Well, OK then. We can move them there for a couple of years and then they can move back into the old neighbourhood. But...hang on. The owners of the buildings have improved them. It's now an area that decent, law abiding people want to live. As opposed to a place where 'drug dealing and prostitution occured, and where crime was rampant to the point the police stopped responding to calls'.
Let's agree on something else! This new area, this updated, upgraded zone is now going to cost more to live in. So where do the people who used to live there go now? Yeah...I know, there aren't really any vacant slums to house people until all this happened. We just threw that in to get to this point. All the slums are now decent places to live. And all those who used to live there now have nowhere to go. And a lot end up on the street.
How do you solve this problem? I really am interested.