You know why it's crowded? it's because they have a large population cramped into the nile valley and delta and everything outside of its is uninhabitable desert. It kinda reminds me of Hong Kong in a way in how crowded it is and how so many people are being fit into a small area.
For example campare libyas population , it's only 6.9 million because most of it is a barren desert.
They crammed 102 million people into a space the size of Slovakia. The red is Egypt true shape.
That's not really the bigger issue, large parts of cairo is actually lacks sanitary affordable housing, which makes the issue even worse. So consequently they are building all these informal settlements and cramped apartments.
What cairo should do to combat the overcrowding in my opinion was to clear out some desert areas and dig extended canal into them that transfers a portion of the river water to irrigate it and build new affordable settlements in those areas, with transportation mechanism that connects it.
Instead of doing that they are bankrupting the country by building expensive vanity project. They have made several failed previous attempts to unload the population into the sahara desert , projects like 4th october city (1979), Al-Bour(1990, Ramadan City(1999) and New Cairo(2000) but only high income people with cars could move into them and it eventually led them to become more like deserted cities and not desert cities. The building