Food crisis and overpopulation are obviously two topics which are closely related on many levels. In countries where overpopulation of urban areas creates additional problems such as poverty, crime and public health issues, food crisis is also oftentimes an accompanying problem. India, China, Bangladesh, and a number of other nations experience problems with overcrowded urban areas, but in some cases poverty is the worst aspect of overopulation. Still, in some parts of more affluent cities (such as Tokyo) overcowding yields other problems. Major cities that experience large-scale emergencies (such as storms or power outages) find that food supplies may dwindle dangerously quickly often due to overbuying/hoarding by some citizens, or price-gouging by vendors. Because rural areas often grow foodstuffs or raise livestock, they are closer to food supplies than those who live in cities, who must rely on food being delivered by truck, train or boat. Crises in major urban areas can cause a shutting down of the infrastructure that allows regular food delivery; this is one reason American government emergency planning programs recommend keeping at least a week's worth of provisions on hand.