Question: What is the bus system called in the city where Spectre was filmed after filming in the city that once headquartered the political party of Antonio Gramsci?

full_context: Document 1: Ant (newspaper): Ant ('Oath') was a weekly leftwing publication in Turkey, which first appeared in 1967. "Ant" supported the Workers Party of Turkey (TİP), and sought to resolve the differences between the TİP and other sectors of the left. "Ant" stressed that the struggle for socialism and the struggle against imperialism had to be combined.
Document 2: Jiří Pernes: Between 1984-1990 he was director of the Historical Museum in Slavkov u Brna (Austerlitz), then between 1990-1992 he was director of the Moravské zemské muzeum in Brno. In 2011 he directed the Institute for the Study of Totalitarian Regimes. Jiří Pernes held lectures at the Masaryk University in Brno and at the Jan Evangelista Purkyně University in Ústí nad Labem.
Document 3: Jiří Pelikán (politician): Jiří Pelikán (7 February 1923 in Olomouc, Czechoslovakia – 26 June 1999 in Rome, Italy) was a Czechoslovakian journalist and member of parliament, then a member of the European Parliament for the Italian Socialist Party.
Document 4: Spectre (2015 film): Whilst filming in Mexico City, speculation in the media claimed that the script had been altered to accommodate the demands of Mexican authorities—reportedly influencing details of the scene and characters, casting choices, and modifying the script in order to portray the country in a "positive light"—in order to secure tax concessions and financial support worth up to $20 million for the film. This was denied by producer Michael G. Wilson, who stated that the scene had always been intended to be shot in Mexico as production had been attracted to the imagery of the Day of the Dead, and that the script had been developed from there. Production of Skyfall had previously faced similar problems while attempting to secure permits to shoot the film's pre-title sequence in India before moving to Istanbul.
Document 5: Spectre (2015 film): Mendes revealed that production would begin on 8 December 2014 at Pinewood Studios, with filming taking seven months. Mendes also confirmed several filming locations, including London, Mexico City and Rome. Van Hoytema shot the film on Kodak 35 mm film stock. Early filming took place at Pinewood Studios, and around London, with scenes variously featuring Craig and Harris at Bond's flat, and Craig and Kinnear travelling down the River Thames.
Document 6: Mexico City: By the 1990s Mexico City had become infamous as one of the world's most polluted cities; however the city has become a model for dramatically lowering pollution levels. By 2014 carbon monoxide pollution had dropped dramatically, while levels of sulfur dioxide and nitrogen dioxide were nearly three times lower than in 1992. The levels of signature pollutants in Mexico City are similar to those of Los Angeles.[citation needed] Despite the cleanup, the metropolitan area is still the most ozone-polluted part of the country, with ozone levels 2.5 times beyond WHO-defined safe limits.
Document 7: Mexico City: To clean up pollution, the federal and local governments implemented numerous plans including the constant monitoring and reporting of environmental conditions, such as ozone and nitrogen oxides. When the levels of these two pollutants reached critical levels, contingency actions were implemented which included closing factories, changing school hours, and extending the A day without a car program to two days of the week. The government also instituted industrial technology improvements, a strict biannual vehicle emission inspection and the reformulation of gasoline and diesel fuels. The introduction of Metrobús bus rapid transit and the Ecobici bike-sharing were among efforts to encourage alternate, greener forms of transportation.
Document 8: Spectre (2015 film): With filming completed in Rome, production moved to Mexico City in late March to shoot the film's opening sequence, with scenes to include the Day of the Dead festival filmed in and around the Zócalo and the Centro Histórico district. The planned scenes required the city square to be closed for filming a sequence involving a fight aboard a Messerschmitt-Bölkow-Blohm Bo 105 helicopter flown by stunt pilot Chuck Aaron, which called for modifications to be made to several buildings to prevent damage. This particular scene in Mexico required 1,500 extras, 10 giant skeletons and 250,000 paper flowers. Reports in the Mexican media added that the film's second unit would move to Palenque in the state of Chiapas, to film aerial manoeuvres considered too dangerous to shoot in an urban area.
Document 9: Camilla Ravera: Ravera participated in the founding of the Italian Communist Party in 1921. She was General Secretary of the party from 1927 until 1930 following the arrest of Antonio Gramsci.
Document 10: Spectre (2015 film): A brief shoot at London's City Hall was filmed on 18 April 2015, while Mendes was on location. On 17 May 2015 filming took place on the Thames in London. Stunt scenes involving Craig and Seydoux on a speedboat as well as a low flying helicopter near Westminster Bridge were shot at night, with filming temporarily closing both Westminster and Lambeth Bridges. Scenes were also shot on the river near MI6's headquarters at Vauxhall Cross. The crew returned to the river less than a week later to film scenes solely set on Westminster Bridge. The London Fire Brigade was on set to simulate rain as well as monitor smoke used for filming. Craig, Seydoux, and Waltz, as well as Harris and Fiennes, were seen being filmed. Prior to this, scenes involving Fiennes were shot at a restaurant in Covent Garden. Filming then took place in Trafalgar Square. In early June, the crew, as well as Craig, Seydoux, and Waltz, returned to the Thames for a final time to continue filming scenes previously shot on the river.
Document 11: Mexico City: The World Bank has sponsored a project to curb air pollution through public transport improvements and the Mexican government has started shutting down polluting factories. They have phased out diesel buses and mandated new emission controls on new cars; since 1993 all new cars must be fitted with a catalytic converter, which reduces the emissions released. Trucks must use only liquefied petroleum gas (LPG). Also construction of an underground rail system was begun in 1968 in order to help curb air pollution problems and alleviate traffic congestion. Today it has over 201 km (125 mi) of track and carries over 5 million people every day. Fees are kept low to encourage use of the system and during rush hours the crush is so great, that authorities have reserved a special carriage specifically for women. Due to these initiatives and others, the air quality in Mexico City has begun to improve, with the air becoming cleaner since 1991, when the air quality was declared to be a public health risk for 355 days of the year.[citation needed]
Document 12: L'Ordine Nuovo: L'Ordine Nuovo (Italian for "The New Order") was a weekly newspaper established on May 1, 1919, in Turin, Italy, by a group, including Antonio Gramsci, Angelo Tasca and Palmiro Togliatti, within the Italian Socialist Party. The paper was the successor of "La Città futura", a broadsheet newspaper. The founders of "L'Ordine Nuovo" were admirers of the Russian Revolution and strongly supported the immediate creation of soviets in Italy. They believed that existing factory councils of workers could be strengthened so that they could become the basis of a communist revolution. However, Amadeo Bordiga, who would become the founder of the Communist Party of Italy, criticised the plan as syndicalism, saying that soviets should only be created after Italy had come under communist control.
Document 13: New class: A theory of the new class was developed by Milovan Đilas the Vice President of the Federal People's Republic of Yugoslavia under Josip Broz Tito, who participated with Tito in the Yugoslav People's Liberation War, but was later purged by him as Đilas began to advocate democratic and egalitarian ideals (which he believed were more in line with the way socialism and communism should look like). However, there were also personal antagonisms between the two men, and Tito felt Đilas undermined his leadership. The theory of the new class can be considered to oppose the theories of certain ruling Communists, such as Joseph Stalin, who argued that their revolutions and / or social reforms would result in the extinction of any ruling class as such. It was Đilas' observation as a member of a Communist government that Party members stepped into the role of ruling class -- a problem which he believed should be corrected through revolution. Đilas' completed his primary work on his new class theory in the mid-1950s. While Đilas was in prison, it was published in 1957 in the West under the title The New Class: An Analysis of the Communist System.
Document 14: Air pollution in Mexico City: It has been said that ``Mexico City's air has gone from among the world's cleanest to among the dirtiest in the span of a generation. ''Historic air pollution episodes of the 1950s led to acute increases in infant mortality.
Document 15: Jiří Dienstbier Jr.: Jiří Dienstbier Jr. is the son of Jiří Dienstbier Sr., former journalist and civil rights activist who became the first Minister of Foreign Affairs in the newly democratic Czechoslovakia, and Zuzana Dienstbierová, née Wíšová, a psychologist. His parents and his grandfather, Jaromír Wíšo, were signatories to the Charter 77 human rights declaration. Consequently, Dienstbier's family experienced intense political pressure from the Communist regime during the "Normalization" period after 1969. While Jiří Dienstbier Jr was 10 years old, his father was imprisoned for his work in a movement acting parallel to Charter 77, the Committee for the Defense of the Unjustly Prosecuted (; VONS).
ground_truth: Metrobús
sub_queries: Antonio Gramsci >> member of political party Answer: Italian Socialist Party
Italian Socialist Party >> headquarters location Answer: Rome
Where did Spectre filming take place after Rome ? Answer: Mexico City
What is the bus system called in Mexico City ? Answer: Metrobús