Overpopulation has led to many negative environmental impacts in the developing world. Probably the most critical area in water use. Population have grown to exceed the amount of usable water for both agriculture and drinking. The lack of safe drinking water contributes to epidemic diseases and high child mortality rates. Many rivers are so heavily used for irrigation that they run dry before reaching their mouths, degrading or destroying fish habitat and downstream agriculture. Another major problem is deforestation, especially in the Amazon, where excess population causes people to chop down massive areas of rain forest to grow crops and raise animals. Because farmland cannot sustain rapidly expanding rural populations, there has been dramatic urbanization, with the rural poor moving to cities leading to the development of massive slums such as the favelas of Brazil and the notorious slums of Mumbai. Population pressures are also responsible for wars and civil unrest.
Population growth is a curse for developing countries, especially at the rate at which it is growing. Developing countries are characterized by a shortage of resources, developing infrastructures and increasing environmental degradation (due to the harvesting of resources), among other difficulties. In such a scenario, population growth simply means the division of already scarce resources, incremental environmental impacts and incremental strains on infrastructure. For example, the rate of population growth in most of the developing countries far exceeds the capacity building or infrastructure growth. This translates into more traffic congestion, higher air pollution, higher rates of resource excavation/production and utilization, water scarcity and a greater burden on the environment. Population expansion also means more mouths to feed, more children to teach and more job requirements. Typically, population growth exceeds the capacity development in these areas, leading to more cases of infant mortality and malnutrition, higher crime rates and civic unrest and diseases.