Mexico City's Fight Against Pollution: Strategies And Initiatives

Mexico City has long been known for its poor air quality, with the United Nations declaring it the most polluted city in the world in 1992. However, in recent years, the city has made significant strides in reducing pollution and improving air quality. One of the most notable efforts is the Hoy No Circula policy, which restricts vehicles from being driven one day a week and two Saturdays per month. The city has also expanded its public transportation options, including low- and zero-emission choices like the Metrobús and Ecobici bicycles, and introduced hybrid and electric taxis. In addition, Mexico City has implemented clean energy initiatives, such as removing lead from gasoline, reducing sulphur content in diesel fuel, and closing oil refineries. These efforts have had a positive impact, with Mexico City dropping to the 917th most polluted city in the world in 2021.

Closing fuel refineries

In the 1980s and 90s, Mexico City was labelled the world's most polluted city. This was due to a combination of industrialisation, urbanisation, and a proliferation of vehicles, which led to high levels of ground-level ozone, carbon monoxide, sulphur dioxide, nitrogen dioxide, and airborne particles.

In response, the Mexican government implemented a range of policies to combat air pollution. One notable policy was the "Hoy No Circula" ("No-Drive Days") programme, which prohibited drivers from using their vehicles one weekday per week. However, this policy was not effective in the long term, as people simply bought additional cars to drive on the restricted days.

Recognising the limitations of "Hoy No Circula", the city's government launched the ProAire programme in 1995. This extensive programme included several concrete measures to achieve sustainable development, including the closure of fuel refineries, the addition of catalytic converters to cars, and the introduction of low- and zero-emissions public transit options.

The closure of fuel refineries was a significant step in reducing air pollution in Mexico City. By addressing the issue at the source, the government was able to decrease the emissions of harmful pollutants and improve the city's air quality. This action, along with other initiatives, contributed to a significant improvement in Mexico City's air quality, dropping its ranking from the most polluted city in the world in 1992 to the 917th most polluted city in 2021.

The success of these measures demonstrates the importance of addressing air pollution at its source and the effectiveness of implementing comprehensive programmes that address multiple aspects of the issue. While there is still work to be done, Mexico City's efforts provide a model for other cities facing similar challenges.

Catalytic converters on cars

Mexico City's air pollution has been a concern for its population and health officials for decades. In the 20th century, the population of Mexico City rapidly increased as industrialization brought thousands of migrants from around the world. This population boom, coupled with the proliferation of vehicles and rapid industrial growth, led to severe air quality issues.

In 1992, the United Nations named Mexico City "the most polluted city on the planet". Since then, the Mexican government has implemented various plans to reduce emission levels, including the ProAire program, which includes several concrete measures to achieve sustainable development. One of the most notable policies has been the "Hoy No Circula" ("No-Drive Days"), which prohibits drivers from using their vehicles one weekday per week and two Saturdays per month.

Another important measure to reduce emissions has been the addition of catalytic converters to automobiles. In the past, most cars in Mexico City ran on unleaded petrol and could not use catalytic converters. However, in the 1990s, the government implemented a plan to add catalytic converters to cars as part of the ProAire program. This measure has helped to reduce emissions and improve air quality in the city.

Catalytic converters are essential devices that help reduce harmful vehicle emissions. They work by converting toxic gases and pollutants from a car's exhaust into less harmful substances. These devices are typically made of precious metals like platinum, palladium, and rhodium, which act as catalysts in the chemical reaction that transforms harmful gases into less harmful ones.

The addition of catalytic converters to cars in Mexico City has had a significant impact on reducing emissions and improving air quality. However, it is important to note that there have been some challenges and limitations to their implementation. For example, some older cars with carburetor-equipped engines may not have been compatible with catalytic converters, and there have been reports of people removing the converters after entering Mexico due to the lack of uniform requirements across the country.

Despite these challenges, the use of catalytic converters in Mexico City has been an important step towards improving the city's air quality and reducing the health risks associated with air pollution. By reducing the emissions of harmful gases such as carbon monoxide, nitrogen oxides, and hydrocarbons, catalytic converters play a crucial role in creating a cleaner and healthier environment for the city's residents.

'No-drive days'

In 1989, the Mexican government introduced "No-Drive Days", also known as "Hoy No Circula", which prohibited drivers from using their vehicles one weekday per week. In 2008, this rule was changed to include Saturdays, meaning drivers were prohibited from driving two days a week. The scheme was first introduced to combat the high levels of air pollution in Mexico City, which was declared the world's most polluted city by the UN in 1992.

Under the scheme, all vehicles are required to go through emissions testing every six months. Each vehicle is then issued a verification depending on its performance in the test. Vehicles that meet the requirements are assigned "0", while underperforming vehicles are assigned "1" or "2". Cars with a "0" rating are exempt from the "Hoy No Circula" scheme, while those with "1" and "2" ratings are prohibited from being driven on one weekday and two Saturdays per month.

Despite the introduction of "No-Drive Days", the effectiveness of the scheme has been questioned. Rather than using public transport, some people chose to buy another car to drive on the restricted days, meaning that sales of automobiles increased. In recognition of this, the city's government launched an extensive programme in 1995 called ProAire, which included measures such as the renewal of the bus fleet and the expansion of the city's subway network and bike-sharing initiatives.

In 2019, Mexico City joined several other cities across the country by becoming a BreatheLife member and establishing an air quality monitoring system and an emissions inventory. The city has also implemented clean energy efforts, such as removing lead from gasoline, reducing sulphur content in diesel fuel, closing an oil refinery, and reformulating liquified petroleum gas for cooking and heating.

Air quality forecasting

The air quality forecasting system focuses on nanoparticles, which are primarily released through vehicle emissions and industrial activity. These nanoparticles pose significant health risks as they can lodge themselves in people's lungs and hearts, leading to long-term health consequences. Accurate prediction of high pollution levels enables authorities to take necessary steps, such as cancelling school classes, and allows residents to plan their activities and transport accordingly.

The air quality forecasting system is part of a multiphase government program called ProAire, which has been recognised for its positive impact on the city's air quality. The program has included measures such as closing fuel refineries, adding catalytic converters to cars, and implementing weekly "No-Drive Days."

Mexico City's efforts to improve air quality have not gone unnoticed, and it was awarded the C40 and Siemens Climate Leadership Awards' Air Quality category in 2013. The city's successful implementation of ProAire serves as a model for other cities facing similar air pollution challenges.

Solar panel integration

Mexico City has been taking steps to reduce its air pollution, which has been a concern for decades. One of the key initiatives is the integration of solar panels to harness the abundant solar energy in the region.

Mexico City's solar panel integration efforts are led by the "Ciudad Solar" (Solar City) program, which aims to harness 350 megawatts of solar energy by 2024. The city government has committed nearly 8 billion pesos ($414 million) to this initiative, with funding from various sources, including the city budget, the Mexican federal bank Nacional Financiera (NAFIN), the World Bank, and the Inter-American Development Bank.

One of the most notable projects under this program is the installation of over 32,000 photovoltaic modules on the rooftops of the Central de Abasto, the city's primary wholesale market for vegetables, fruits, and meat. This project, covering about 220,000 square meters (54 acres), will generate approximately 25 gigawatt-hours of electricity annually, primarily to power the market itself, resulting in a reduction of 13,550 tons of CO2 emissions per year.

The Solar City program also includes the installation of renewable energy units, such as solar panels and solar heaters, across private and public buildings over five years. This initiative is expected to reduce carbon emissions by 2 million tons, significantly improving the air quality in Mexico City.

Mexico has favourable conditions for solar power, with 70% of the country having an insolation of greater than 4.5 kWh/m2/day. The country has recognised the potential of solar energy and has been working towards increasing its solar capacity. In 2013, 0.1% of Mexico's installed electricity generation capacity came from solar PV, but this figure is expected to grow.

In 2015 and 2016, Mexico held its first long-term energy auctions, in which solar PV was successful, securing a significant portion of the auctioned capacity. The Villanueva Solar plant, located in Mexico, is the largest in the country, with 310 MW installed by mid-2018 and an expected capacity of 828 MW upon completion, making it the largest in the Americas.

Additionally, Mexico has a favourable regulatory framework for distributed generation, with policies like net metering, which allow excess energy generated by solar panels to be fed back into the grid. This has led to a growing trend of installing solar panels on rooftops and small businesses, with a significant increase in installed capacity from 3 kW in 2007 to 247.6 MW by the end of 2016.

The integration of solar panels in Mexico City and the country as a whole is a crucial step towards reducing pollution and transitioning to cleaner energy sources. With continued investment and favourable policies, Mexico is well-positioned to capitalise on its abundant solar resources and further improve its air quality.

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