High population density
High population density means there is not a lot of space for other people. That means it is crowded.
Why are some places more crowded than others?
Because people want to live in certain places with nice stuff.
Some people want to live in hot places or cold places.
People live near things they want to live by.
Some places have hurricanes.
There are fires in some places.
Some places have no water.Some places have more water.Some places have a little water.
When a lot of people live in another place it is easier to get what you want.
Higher population=more job opportunities.
It might be easier to find what you need in a big city, but you have to share.