What are the main economic problems due to overpopulation?

One of
the main economic problems for any country with an overpopulation problem is the shortage of
food, minerals, fuel and other resources. This applies particularly to third world countries
where harvest failure and famine are frequent. Populations which survive on subsistence farming
are particularly badly hit, as without their crops and animals they will starve. Such people are
only able to support themselves in the most basic way, and do not have disposable income to pay
taxes with. The result of this sort of overpopulation is that there is no money in the country's
kitty or treasury to provide social security, pensions or a basic health service for a
burgeoning population. Some countries have even put a limit on the number of children families
can have.