Il Related Information: (1)Mexico City Mexico City: the capital and industrial and cultural center of Mexico, is now the world's largest city. The metropolitan area had an estimated 22. 2 million inhabitants in 1990. The population of the federal district(the administrati ve area within which the city is located), quadrupled between 1950 and 1990. It is still growing at a rapid pace, with 200o newcomers arriving each day, mainly from impoverished rural areas. An estimated 50 percent of the city's inhabitants live as squatters in illegal dwellings. Because of the increasing number of inhabitants and major expansion of industry, the city faces many serious problems. It suffers from periodic water shortages. Many city residents now suffer from respiratory ailments caused by the tremendous air pollution as more than 3.5 million cars, trucks, buses, and motorcycles still emit poisonous fumes into the air Text B of Unit Ten Yang XingfangText B of Unit Ten Yang Xiongfang II. Related Information: (1) Mexico City Mexico City: the capital and industrial and cultural center of Mexico, is now the world’s largest city. The metropolitan area had an estimated 22.2 million inhabitants in 1990.The population of the federal district (the administrative area within which the city is located), quadrupled between 1950 and 1990. It is still growing at a rapid pace, with 200o newcomers arriving each day, mainly from impoverished rural areas. An estimated 50 percent of the city's inhabitants live as squatters in illegal dwellings. Because of the increasing number of inhabitants and major expansion of industry, the city faces many serious problems. It suffers from periodic water shortages. Many city residents now suffer from respiratory ailments caused by the tremendous air pollution as more than 3.5 million cars, trucks, buses, and motorcycles still emit poisonous fumes into the air