Land degradation is the undermining of the quality of soil as a result of human behavior or severe weather conditions. A form of land degradation that occurs when arable land becomes desert is known as desertification.
Drought, flooding and human activities, such as deforestation, agriculture and urbanization, can all put multiple pressures on fertile land, causing the soil to become degraded or polluted, according to the World Health Organization. This process of reducing the quality of soil is called land degradation, and it can put stress on the environment, affecting the production of food, as well as the quality of air and water.
An extreme form of land degradation is desertification, in which land becomes too dry to support vegetation or wildlife as water sources diminish. Without adequate water supplies, there is poor hygiene and more pollutants in the air, such as dust from soil erosion, which can result in infectious diseases.
People and animals living on arid, degraded land need to move to surroundings more conducive to supporting life, which puts resource pressures on water and food supplies for other places as their populations increase. Mass migration from degraded land can also be a major factor in the spread of diseases.