September of last year 54 died in a fire because trucks couldn't get close enough to fight the fire (not to mention no fire exits, bars on windows, people couldn't escape).
This past May fourteen died in a fire. Fire department was handing out axes and told resident to bust through walls if a fire happened.
Some photos here, but these are relatively decent houses, many of them not illegal, just built long ago. They get much, much more complex and much, much more run down condition, including lots of illegal construction.
There are plenty of illegal buildings, modified for residence in a haphazard manner with shoulder-width roads passing underneath them.