Cairo is the capital and largest city of Egypt, as well as the largest city in Africa and even the Arab world. Since 1984, its population has grown from about 8 million to more than 22 million, with a population density of more than 19,000 people per square kilometer, and the population is still rising. Growing with the rising population are many problems such as garbage, congestion and pollution, and in particular, the lagging garbage disposal system. The increasing amounts of garbage that can not be timely, efficient and environmentally friendly recycled and disposed, are stacked in the most traditional way, forming a famous garbage city of Manshiyat Nasser at the foot of Mokattam Mountain.