“Greater Mexico City”的意思、由来-开放百科全书

Greater Mexico City refers to the conurbation around Mexico City, officially called Valley of Mexico Metropolitan Area (Zona Metropolitana del Valle de México),^[1] constituted by Mexico City itself composed of 16 Municipalities—and 41 adjacent municipalities of the states of Mexico and Hidalgo. For normative purposes, however, Greater Mexico City most commonly refers to the Metropolitan Area of the Valley of Mexico (Zona Metropolitana del Valle de México) an agglomeration that incorporates 18 additional municipalities. {{As of|2016}} an estimated 21,157,000 people lived in Greater Mexico City,^[2] making it the largest metropolitan area in North America. It is surrounded by thin strips of highlands which separate it from other adjacent metropolitan areas, of which the biggest are Puebla, Toluca, and Cuernavaca-Cuautla, and together with which it makes up the Mexico City megalopolis.

Since the 1940s there have been different proposals to establish the limits of the growing conurbation of Mexico City, and different definitions were used unofficially as the city continued to grow. The Federal Government (represented by the Department of Social Development), the government of Mexico City, and the government of the State of Mexico agreed on the official definitions for both the Mexico City Metropolitan Area and the Metropolitan Area of the Valley of Mexico on 22 December 2005.^[2] Per the agreement, most urban planning projects will be administered by Metropolitan Commissions.

On January 29, 2016, Mexico City proper was no longer called the Federal District (Spanish: "Distrito Federal" or D.F.). It is now in transition to become the country's 32nd federal entity, officially "City of Mexico" (Spanish: "Ciudad de México", commonly abbreviated as "CDMX"), giving it a level of autonomy comparable to that of a state. Because of a clause in the Mexican Constitution, however, since it is the seat of the powers of the federation, it can never become a state, or the capital of the country has to be relocated.^[3] The English name "Mexico City" remains. Its original 16 "Boroughs" became "municipalities".

Components of the agglomeration

Mexico City Metropolitan Area

Another way to visualize these municipalities is by their intrastate regions. The Mexico City Metropolitan Area fully covers 5 regions (regiones naturales) in Mexico State, partly covers another 5 regions, the Federal District, and 1 municipality in Hidalgo.

Metropolitan Area of the Valley of Mexico

The definition of the Mexico City Metropolitan Area is positive, in that all municipalities form a single conurbation. By contrast, the Metropolitan Area of the Valley of Mexico is considered a normative definition, in that it incorporates 18 additional strategic municipalities in the territorial administration of the region, even if they have not been fully integrated yet. Many urban projects, mostly related to the improvement of air quality and water sanitation, are coordinated for all constituent municipalities of this agglomeration. The majority of the population reports of urban areas in Mexico refer to this agglomeration, and not to the MCMA conurbation.

Note that all municipalities are within the Metropolitan Area of the Valley of Mexico. Together these 10 intrastate regions cover every single municipality within the Valley of Mexico Metropolitan Area except for the 1 municipality in Hidalgo State. (59 municipalities):

Geography and environment

Greater Mexico City spreads over the valley of Mexico, also called the valley of Anáhuac, a 9,560 km² (3,691 sq mi) valley that lies at an average of 2,240 m (7,349 ft) above sea level. Originally, a system of interconnected lakes occupied a large area of the valley, of which Lake Texcoco was the largest. Mexico City was built on the island of Tenochtitlan in the middle of the lake. During conquest of Mexico the dikes that protected the city from recurrent floods were destroyed and colonial authorities preferred to drain the water of the lake, which was, for the most part, shallow. In 1900 president Porfirio Díaz inaugurated the Valley's System of Drainage that hinders the growth of water bodies in the valley (and prevents floods). The basin of the valley of Mexico was thus integrated artificially to the Moctezuma river basin which connects to the Pánuco River. The last remnants of the system of lakes are found in the boroughs of Xochimilco and Tláhuac, and in the municipality of Atenco.

The valley of Mexico is surrounded by mountains on all four sides creating a basin with only one small opening at the north, trapping all exhaust emissions of the city. At the southern part of the basin the mountain range reaches an altitude of 3,952 m (12,965 ft) above sea level; and to the east the volcanoes reach an altitude of more than 5,000 m (16,000 ft). The region receives anti-cyclonic systems, producing weak winds that do not allow for the dispersion of accumulated air pollutants, produced by the 50,000 industries operating in Greater Mexico City and the 4 million vehicles circulating in its roads and highways.^[4]

There are several environmental programs in operation in all municipalities of Greater Mexico City. One of them is Hoy No Circula (known in English as "One Day without a Car"), whereby some vehicles with certain ending numbers on their license plates are not allowed to circulate on certain days in an attempt to cut down on pollution and traffic congestion. The program groups vehicles by their ending license plate digits, and every weekday vehicles having any of the day's two "hoy no circula" digits are banned from circulating. For instance, on Fridays, vehicles with plates ending in 9 or 0 may not drive. This program is controversial since it has resulted in households buying additional vehicles, either new cars for better-off houses, or very old cheap—and thus more polluting—vehicles. Moreover, newer vehicles are exempt from complying with the program—in that they are manufactured with stricter pollution-reduction equipment—a move said to have been pushed by auto makers to boost sales of new vehicles{{Citation needed|date=March 2016}}.

Other environmental programs include the IMECA (Índice Metropolitano de la Calidad del Aire, "Metropolitan Index of Air Quality") a real-time monitoring of the concentrations of several pollutants on the atmosphere of the valley of Mexico. If the IMECA values reach a critical level, an environmental contingency is declared whereby Hoy No Circula is extended to two days per week, industrial activities are reduced, certain gas power plants shut down, and elementary school entry hours are changed. There has been a decrease in the number of environmental contingencies since the 1990s (due, among other reasons, to the implementation of industrial controls and to the relocation of some factories), from more than 5 to only one or zero a year in the last few years{{Citation needed|date=March 2016}}.

Political administration

Like it is the case with all trans-municipal metropolitan areas in Mexico, there is no elected government institution in charge of administering the entire metropolitan area. Each municipality is autonomous to administer its local affairs, regulated by the government of the states they belong to. However, unlike some other large metropolitan areas that are entirely contained in one state, like Greater Guadalajara and Greater Monterrey in which the state government coordinates metropolitan activities, Greater Mexico City spreads over three federal entities—two states and the Federal District—and therefore most of the metropolitan projects have to be agreed upon by government officials of each federal entity and/or overseen by the federal government—since the budget of the Federal District is approved by the Congress of the Union, being the capital of the federation—or through metropolitan commissions.

Economy

From 1940 and until 1980, Greater Mexico City experienced an intense rate of demographic growth concurrent with the economic policy of import substitution. Mexican industrial production was heavily centralized in Greater Mexico City during this period which produced intense immigration to the city. Close to 52% of the economically active population of Greater Mexico City worked in the industry sector in 1970.^[5] This situation changed drastically during the period of 1980 to 2000, in which the economic based shifted to the service sector which in 2000 employed close to 70% of the economically active population in the conurbation.^[5] The annual rate of growth decreased sharply as well as the regional and national patterns of immigration: residents are moving out of the core city to the suburbs or to nearby cities, whereas the northern states now receive a larger number of immigrants as new hubs of industrial production. Greater Mexico City's main industries are now related to trade, financial services, insurance companies, telecommunications, informatics and transportation.^[5] In spite of the recent shifts in economic production and the decentralization of the economic activity promoted by the government, Greater Mexico City's share of total economic activity in the country is still high, though decreasing. Mexico City proper alone produces $170 billion or 17% of the nation's Gross Domestic Product, larger than any of the states.^[6]

Areas by human development index

According to the Human Development Report of 2005^[7] most metropolitan municipalities had a high human development index. Coacalco de Berriozábal had the highest value in the State of Mexico metropolitan area (.9045), the second highest in the whole state after Metepec (Greater Toluca) and the fourth in Greater Mexico City after the boroughs of Benito Juarez, Miguel Hidalgo and Coyoacán making it the 10th nationally. Coacalco was followed by Cuautitlán Izcalli (.9023) which had a very high HDI as well, Cuautitlán (.8919), Atizapán de Zaragoza (.8858) Tlalnepantla de Baz (.8854), Huixquilucan de Degollado (.8843), Jaltenco (.8772), Naucalpan de Juárez (.8754), Tultitlán de Mariano Escobedo (.8700) and Tecámac (.8669).

Even though some of these municipalities have some of the wealthier neighborhoods of the city, they often contrast with peripheric low income suburbs known as zonas marginales or ciudades perdidas. This is the case of the wealthy suburb of Tecamachalco contrasting with El Molinito shanty town, both in Naucalpan, Chamapa in Naucalpan next to Bosque Real Country Club in Huixquilucan and Zona Esmeralda residential area in Atizapán with Atizapán de Zaragoza seat and Ciudad Nicolás Romero which also contrasts with the residential area of Bosques del Lago in Cuautitlán Izcalli.

Marginal municipalities in the east such as Ciudad Nezahualcóyotl (.8621), Ecatepec de Morelos (.8597), Valle de Chalco (52nd in the state and 452nd nationally) with .8128 and Chimalhuacán with .8086 (56th in the state and 508 nationally) also presented high HDI values, nevertheless the last two fell among the lowest of Greater Mexico City. Municipalities with a Medium HDI were Ozumba (.7983 61st), Temascalapa (.7982 62nd), Otumba (.7932 66th), Jilotzingo (.7908 68th), Juchitepec (.7874 72nd), Isidro Fabela (.7791 78th), Axapusco (.7768 80th), Hueypoxtla(.7666 82nd), Nopaltepec (.7661 83rd), Atlautla (.7624 86th), Ecatzingo (.7291 99th) and Villa del Carbón (.7172 104th). However, all of these municipalities are still out of Mexico City's main urban area and are considered rural.

Demographics

Greater Mexico City is the largest metropolitan area in Mexico and the area with the highest population density. As of 2016, an estimated 21,157,000 persons live in this metropolitan area,^[8] of which 8,841,916 live in Mexico City proper.^[9] In terms of population, the biggest municipalities that are part of Greater Mexico City (excluding Mexico City proper) are:^[10]

The above municipalities are located in the state of Mexico; in fact, approximately 75% (10 million) of the state of México's population live in municipalities that are part of Greater Mexico City's conurbation.

Greater Mexico City was the fastest growing metropolitan area in the country until the late 1980s. Since then, and through a policy of decentralization in order to reduce the environmental pollutants of the growing conurbation, the annual rate of growth of the agglomeration has decreased, and it is lower than that of the other four largest metropolitan areas (namely Greater Guadalajara, Greater Monterrey, Greater Puebla and Greater Toluca) even though it is still positive.^[11] The net migration rate of Mexico City proper from 1995 to 2000, however, was negative,^[12] which implies that residents are moving to the suburbs of the metropolitan area, or to other states of Mexico. In addition, some inner city suburbs are losing population to outer city suburbs, indicating continual expansion of Greater Mexico City.

Transportation

Greater Mexico City is connected through a private network of toll expressways to the nearby cities of Querétaro, Toluca, Cuernavaca, Pachuca and Puebla. Ring roads are the Circuito Interior (inner ring), Anillo Periférico; the Circuito Exterior Mexiquense ("State of Mexico outer loop") toll road skirting the northeastern and eastern edges of the metropolitan area,^[13] the Chamapa-La Venta toll road skirting the northwestern edge, and the Arco Norte completely bypassing the metropolitan area in an arc from west (Toluca) to north (Tula) to east (Puebla). A second level (where tolls are charged) of the Periférico, colloquially called the segundo piso ("second floor"), was officially opened in 2012, with sections still being completed.^[14] The Viaducto Miguel Alemán crosses the city east-west from Observatorio to the airport. In 2013 the Supervía Poniente opened, a toll road linking the new Santa Fe business district with southwestern Mexico City. Inside the city, ejes viales; high-volume, mostly one-way roads, cross the city from side to side in a vast numbered system.

The most important public transportation is the metro, one of the largest in the world with 226 km and 195 stations, that services Mexico City proper, with some service in Ciudad Nezahualcoyotl and Ecatepec. It is further extended by the Xochimilco Light Rail and the lines A and B. A commuter train, the Tren Suburbano, serve several municipalities of the metropolitan area since it started operating by mid-2007, with new lines planned.

Bus and trolleybus transportation is provided by multiple agencies. Bus rapid transit (BRT) services operate: since 2005 Metrobús in Mexico City and since 2010 Mexibús in the State of Mexico.

Unlike other large metropolitan areas, Greater Mexico City is served by only one airport, the Mexico City International Airport or best known as Benito Juárez International Airport, whose traffic exceeds the current capacity. The 2000-2006 federal administrations proposed the construction of a second airport for the metropolitan area to be located at the municipality of Texcoco. Local residents, however, opposed the project, and the government decided to build a second terminal on the restricted area of the current airport, and decentralize flights to the nearby metropolitan areas of Toluca, Puebla, Pachuca and Cuernavaca, which, along with Greater Mexico City, form the Mexico City megalopolis (known in Spanish as the corona regional or a ciudad-región).^[15]

Landmarks

Important landmarks of Greater Mexico City include the Historic Center of Mexico City, the floating gardens of Xochimilco, the Pre-Hispanic city ruins Teotihuacan, located at the municipality of the same name, all three declared World Heritage sites by UNESCO in 1987. The National Parks at the southern portion of the Federal District (over the mountainous range of Ajusco), the Parks of Popocatépetl and Iztaccíhuatl and the National Reserve of Lake Texcoco are some environmental landmarks of the valley as well.