Mexico City: ProAire (1990)

Last Updated: August 28, 2023

In the 1980’s, the pollution in Mexico City was so bad birds were reportedly falling dead from the sky mid-flight. Locals said living there was like smoking two packs of cigarettes a day. Even on a clear day it was difficult to simply see across the street. “You can see it, feel it, taste it, brush it off your clothes and out of the dog’s fur,” according to one report.

The pollution was the result of decades of industrialization that began in the 1940’s. In that time, Mexico City had become home to millions of vehicles without pollution controls, running on toxin- and pollutant-laden fuel, as well as highly polluting oil refineries, power plants and factories. Furthermore, its elevated basin topography and weather patterns meant that these pollutants would be trapped in the metropolitan area.

Despite reports of increased asthma attacks, cancer and neuropsychological disorders, the government’s focus remained on employment and living standards. But public outcry began to grow. Their concern materialized by the writer Carlos Fuentes who renamed the city “Makesicko City” in his novel. U.S. diplomats serving in Mexico City were allowed to retire two years earlier for every year they served there, in compensation for the health effects.

The Policy

In 1992, the United Nations declared Mexico City the most polluted city on Earth. By that point, the government had begun to implement policies to confront it, beginning with the Comprehensive Program Against Air Pollution (PICCA) in 1990. PICCA required new vehicles to include catalytic converters, introduced unleaded gasoline, and established vehicle emissions standards.

In 1995, PICCA became the Program to Improve Air Quality in the Valley of Mexico, or ProAire. ProAire further improved vehicle fuel and emissions inspections and standards, substituted cleaner natural gas for coal and oil in industrial facilities, and relocated high-polluting facilities to outside the metropolitan area. Mexico’s national petroleum industry, PEMEX, began to manufacture cleaner, more efficient fuels.

ProAire III, the third phase of policy, ran from 2002-2010 and called for $12-$15 billion in public and private funding. The more than 80 initiatives under ProAire III included closing the most polluting industrial facilities and improving public transportation to decrease vehicle emissions. This included:

• Expanding the subway system;
• Launching a suburban train system for the sprawling metro area;
• Starting the largest bike-share program in Latin America, EcoBici; and
• Launching Metrobus, a bus rapid transit system running on a fleet of clean, fuel-efficient buses that now carries over a million people each weekday. In addition to reducing air pollution, it is estimated that Metrobus led to an 80,000-ton annual reduction in Mexico City’s carbon footprint.

• Currently, ProAire IV is running from 2011-2020, with measures targeting energy consumption, emissions reduction, continued greening of public transportation, reforestation, and research [1].

Not all the reforms have come without controversy. For example, one of the city’s major reforms was to implement “Hoy No Circula.” Under this program, on each day of the week cars with certain license plate numbers are restricted from being on the road according to whether they end in an odd or even number. There is evidence, however, that to circumvent the restrictions, residents simply purchased second cars or took taxis on no-drive days—leaving some economists to believe that the program did not contribute to improved air quality.

The Impact

The combination of the AQLI’s satellite-derived PM₅ data and Mexico City’s ground-level monitor data shows that particulate pollution has declined by 60.4% since the introduction of the 1990 ProAire policies. [2] Whereas pollution in Mexico City in 1990 is similar to what it is like today in Kolkata and Chhatarpur in India and even more polluted than the most polluted areas in China today, it is now comparable to concentrations in Milan or Warsaw. In terms of life expectancy, that implies a difference of 3.3 years.

Yet, much of that reduction in air pollution had happened by the mid-2000s. It appears that once the lowest-hanging fruit—the easiest pollution to reduce—had been picked, pollution levels stagnated. Since the mid-2000s, concentrations of PM₅ have hovered at more than thrice the WHO guideline; today, the 27.1 million residents of the state of México and Distrito Federal stand to gain 3.3 years of life expectancy on average if the 2021 particulate pollution were brought in compliance with the WHO guideline.

Moving forward, transportation remains the largest source of pollution. Mexico City is a sprawling metropolis, where pollution-emitting commutes can take three hours. Urban restructuring, which would strike at the root of the problem, is financially and practically difficult. Further, pollution policies must not only tackle existing pollution, but also keep up with the city’s rapid growth, lending another challenge to regulators.

[1] To have data dating as far back as 1990, this page uses the Mexico City government’s ground-level monitor data, which differs from the satellite-derived data used in the AQLI map tool. Since PM2.5 was not monitored until 2003 whereas PM10 and TSP have been monitored since 1990, as in the Clean Air Act Policy Impact page, we proceed with the assumption that the ratios between concentrations of PM2.5, PM10, and TSP are constant over time at any given location. With this methodology, it is possible to impute annual average PM2.5 in 1990 for five monitors in and around Mexico City (La Merced, Pedregal, Tlalnepantla, UAM Iztapalapa, and Xalostoc). The results here for pollution reduction and life expectancy saved represent the mean across these five monitoring stations. For more detailed documentation and replication files, click here.

References/Footnotes

[1] https://www.centreforpublicimpact.org/case-study/mexico-citys-proaire-program

[2] To have data dating as far back as 1990, this page uses the Mexico City government’s ground-level monitor data, which differs from the satellite-derived data used in the AQLI map tool. Since PM₅ was not monitored until 2003 whereas PM10 and TSP have been monitored since 1990, as in the Clean Air Act Policy Impact page, we proceed with the assumption that the ratios between concentrations of PM_2.5, PM10, and TSP are constant over time at any given location. With this methodology, it is possible to impute annual average PM_2.5 in 1990 for five monitors in and around Mexico City (La Merced, Pedregal, Tlalnepantla, UAM Iztapalapa, and Xalostoc). The results here for pollution reduction and life expectancy saved represent the mean across these five monitoring stations. For more detailed documentation and replication files, click here.