The Amazon itself is sparsely populated - about 10 million people inhabit an area almost the size of the United States. But the fragile habitat is easily disrupted by the activities of settlers. As the population of Amazon countries continues to increase at a rapid rate, people move into the rainforest lowland, having a dramatic effect on the ecosystem. Local agriculture based on traditional practices is not harmful (see Rainforest Garden), but when land is cleared for grazing and ranching the effect is devastating (see Ranching). Urbanization is also damaging. Besides forest clearing, pollution affects the habitat beyond the boundaries of cities and towns. Satellite imagery effectively illustrates this damage (see Deforestation from Space).