Mexico City's Fight Against Air Pollution

Mexico City has been working to reduce its air pollution since the 1990s, when it was declared the world's most polluted city. The Mexican government has implemented various plans to reduce emission levels, including removing lead from gasoline, reducing sulphur content in diesel fuel, closing oil refineries, and encouraging citizen participation in anti-pollution initiatives. In recent years, Mexico City has continued to pursue key initiatives in its clean air program, including efficient mass transit, solid waste management, energy-efficient buildings, and renewable power supply.

Vehicular restrictions

Hoy No Circula ("Today, Don't Circulate")

Mexico City introduced the "Hoy No Circula" program in 1989, which prohibits drivers from using their vehicles one weekday per week. The restriction is based on the last digit of the vehicle's license plate. For example, vehicles with license plates ending in "5" or "6" cannot be used on Mondays. This program was expanded in 2008 to include Saturdays, with the same restrictions applying. The program has seen high compliance, with city police vigorously enforcing the rules.

Emissions Testing and Verification

In Mexico City and the State of Mexico, all vehicles are required to undergo emissions testing every six months. The vehicles are then issued a verification based on their performance in the test. Vehicles that meet the requirements are assigned "0", while underperforming vehicles are assigned "1" or "2". Vehicles with a "0" verification are exempt from the "Hoy No Circula" program, while those with "1" or "2" are subject to the restrictions.

Promoting Public Transportation

Mexico City has been actively promoting the use of public transportation as an alternative to driving. This includes the expansion of bus rapid transit lines and the introduction of electric taxis. The city is also working on improving the overall efficiency of its transportation systems.

Bicycle-Sharing Systems

Mexico City has implemented bicycle-sharing initiatives to provide a non-polluting mode of transportation for its residents. The city aims to reduce the reliance of its citizens on vehicles and encourage the use of bicycles for shorter distances.

Vehicle Standards and Fuel Regulations

Mexico has also focused on implementing stricter vehicle standards and fuel regulations to reduce emissions. This includes the removal of lead from gasoline, the reduction of sulphur content in diesel fuel, and the reformulation of liquefied petroleum gas used for heating and cooking. These measures have contributed to significant decreases in carbon monoxide, ozone, and particulate matter levels over the years.

Parking and Congestion Pricing

While not specifically a vehicular restriction, Mexico City has also considered implementing congestion pricing and increasing parking fees to discourage driving. These measures aim to make driving more expensive and inconvenient, encouraging residents to use alternative modes of transportation.

Public transport improvements

Mexico City has implemented a range of policies to improve public transport and reduce air pollution.

One notable policy is the "Hoy No Circula" ("today, don't circulate") programme, first introduced in 1989. Under this scheme, all vehicles in Mexico City and the State of Mexico must undergo emissions testing every six months. Vehicles are then issued a verification rating, with "0" assigned to those that meet the requirements, and "1" or "2" to underperforming vehicles. Cars with a "0" rating are exempt from the "Hoy No Circula" programme, while those with "1" or "2" are prohibited from being driven one weekday per week and two Saturdays per month. However, the effectiveness of this policy has been questioned, as people have tended to buy additional cars to drive on restricted days, rather than using public transport.

In recognition of the limitations of the "Hoy No Circula" programme, the city government launched the ProAire initiative in 1995. This extensive programme aims to achieve sustainable development in eight areas, including the promotion of public transport and the regulation of fuel consumption. Under ProAire, Mexico City has implemented several targeted measures, such as the renewal of the bus fleet, the expansion of the subway network, and the introduction of electric taxis and bike-sharing initiatives. The bus fleet renewal aims to minimise unnecessary emissions by amending routes and shifts based on algorithms and introducing buses that meet the EURO V standard.

In addition to these initiatives, Mexico City has also worked to improve public transportation by equipping buses with newer diesel technologies and using green inspectors and remote sensors to identify high-emitting vehicles. These efforts have had a significant impact on the city's air quality and public health. Between 1990 and 2015, the average life expectancy of citizens in Mexico City increased by 3.2 to 3.4 years, and an estimated 22,500 to 28,000 lives were saved.

Green spaces

Mexico City's air pollution has been a concern for its population and health officials for decades. In 1992, the United Nations named it the most polluted city in the world. The Mexican government has since implemented several plans to reduce emission levels, including the ProAire programme, which has been instrumental in improving air quality.

One of the eight themes of ProAire is the expansion of green areas and reforestation. This strategy promotes actions such as the recovery, restoration, conservation, and expansion of urban green spaces to mitigate particle resuspension. It also involves reviewing and modernizing forest fire prevention and combat programmes, as well as reforestation programmes.

In June 2019, the Ministry of Environment's Green Infrastructure Directorate launched the Green Challenge (Reto Verde), a greening strategy to increase the area of public spaces with nature, promote biodiversity, and improve air quality and water management. The original goal was to plant more than 10 million trees and other plants by the end of 2020 in streets, urban parks, protected natural areas, and the region close to the city. The creation of new green spaces is seen as a tool to promote the social use of public space and other environmental benefits.

The Green Challenge involves greening and rehabilitating protected areas, conservation areas, and urban spaces, creating gardens for pollinators, and encouraging active citizen participation. Since 2019, re-vegetation campaigns with citizen participation have been carried out in all municipalities, and interventions have taken place to create and rehabilitate spaces with green areas and infrastructure for sports, culture, and recreation through the seeding parks programme.

Mexico City's commitment to creating more green spaces is also evident in its participation in the Breathe Cities initiative, which aims to reduce air pollution by 30% on average across its participating cities by 2030. As part of this initiative, Mexico City has invested in sustainable, non-motor mobility, such as cycling, and community-focused city planning. The city has introduced electric buses and electric heavy-duty vehicles, developed new cable bus lines, and promoted active travel through a bike-sharing programme and the construction of hundreds of kilometres of new cycle lanes.

The efforts to increase green spaces in Mexico City have resulted in significant air quality improvements, with the city dropping to the 917th most polluted city in the world in 2021.

Air quality monitoring

Mexico City has implemented a range of initiatives to monitor air quality and reduce air pollution.

The Mexican government has been monitoring air quality since the late 1980s, when an automatic air-quality monitoring network revealed high concentrations of lead, carbon monoxide, nitrogen dioxide, sulphur dioxide, ozone, and particulate matter.

In 2017, Mexico City introduced an air quality forecasting system, which can predict high pollution events 24 hours in advance. This allows schools to cancel classes if necessary and gives residents time to plan their activities and transport accordingly.

The Atmospheric Monitoring System (SIMAT) is responsible for the permanent measurement of air pollutants in Mexico City. SIMAT has over 40 monitoring sites in the metropolitan area, which measure criteria pollutants such as sulphur dioxide, carbon monoxide, nitrogen dioxide, ozone, and suspended particles. Some sites also measure meteorological variables, including ultraviolet solar radiation.

Other Initiatives to Reduce Air Pollution

Mexico City has implemented a range of other initiatives to reduce air pollution, including:

• "No-Drive Days" ("Hoy No Circula"), which prohibit drivers from using their vehicles one day per week and two Saturdays per month.
• Requiring vehicles to undergo emissions testing every six months and prohibiting underperforming vehicles from being driven on certain days.
• Improving public transportation, including expanding the subway network and introducing electric taxis.
• Closing polluting factories and moving others out of the city.
• Reformulating gasoline and diesel fuel to reduce lead and sulphur content.
• Substituting fuel oil in industry and power plants with natural gas.
• Reformulating liquefied petroleum gas used for cooking and heating.
• Expanding green spaces, such as the Parque Ecológico Cuitláhuac in Iztapalapa.
• Implementing clean energy initiatives, such as installing solar panels and solar water heaters on public and private buildings.

Energy-efficient buildings

Mexico City has implemented an integrated policy for air quality and climate change, with priority strategies to protect public health. The city has set the improvement of air quality as a policy priority, and through the implementation of these policies, air pollution is maintaining a downward trend, even as the city continues to grow.

Mexico City has committed to improving building efficiency by developing a local partnership with 100 policymakers, businesspeople, and civil society representatives. The city has also introduced tax incentive programs for sustainable buildings and green roofs.

One clear opportunity to improve building efficiency in the short term is to implement existing federal building energy norms as part of the city's building permitting and approvals processes. This would ensure that occupants of all new buildings are guaranteed a minimum level of efficiency.

The city can also improve its municipal buildings to build confidence in the market and encourage local building owners to improve energy efficiency. Innovative financing approaches, such as guarantees, performance contracts, and modified procurement and budgeting rules, can help increase efficiency in existing public buildings.

Projects like the energy improvements at the Universidad Iberoamericana Ciudad de México provide a successful example of what Mexico City can achieve on a larger scale. Through its Green Campus Initiative, the university implemented new technologies that helped reduce energy consumption by 18.6% and avoided the emission of 1,000 metric tons of carbon dioxide per year.

Mexico City has also implemented climate change strategic programs with clear and specific targets, including energy efficiency programs for public buildings. For instance, a new project to convert four public buildings to efficient energy usage was recently approved.

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