Countless numbers of droughts have been recorded throughout history. Nearly every nation has endured a major drought and has suffered from the effects of the drought. Overpopulated areas that experience little annual rainfall, such as India, are in constant danger of drought. Drought represents one of the most important natural triggers for malnutrition and famine, a significant and widespread problem in many parts of Africa and in other countries as well. At least a quarter of the world's population lives in such areas where drought hinders the nations stability and development.
Droughts tend to be more severe in some areas than in others. Catastrophic droughts generally occur in areas bordering the arid regions of the world. When a poleward shift in the prevailing westerlies occurs the high-pressure, anticyclonic conditions of the arid regions effect the climate of areas that normally have wet low-pressure weather. Thus, a drought is started.