In recent months, the air quality in Mexico City and its metropolitan area It has once again become the focus of public debate. Between days with what has been described as "bad" weather, threats of activating phase 1 of the contingency plan, and days when it narrowly escaped... Double No Circulation TodayThe population lives practically glued to the Air and Health index reports.
What is happening in the Mexican capital perfectly reflects the challenges of any large city trying to contain air pollution. traffic restrictions, continuous monitoring, and health alertsAlthough the regulations and thresholds are specific to Mexico, the situation is especially relevant for European cities that are beginning to apply anti-pollution protocols or low-emission zones more strictly.
What is the environmental contingency in Mexico City and when is it activated?
In the Valley of Mexico, the ozone environmental emergency It is declared when monitoring stations record concentrations that exceed 155 points on the air quality index, a value that far exceeds the recommended standard of 90 parts per billion (ppb) for safe exposure.
This threshold is more easily reached on days of high solar radiation, absence of wind and presence of anticyclonic systemsUnder these conditions, pollutants emitted by vehicles and industries accumulate and react in the atmosphere, leading to tropospheric ozone levels that are especially harmful to health.
When phase 1 of the contingency plan is declared, the Megalopolis Environmental Commission (CAMe) immediately tightens traffic restrictions with the well known Double No Circulation Today and issues health recommendations to limit exposure to the outdoors, especially for the most vulnerable groups.
In the absence of a contingency, the system operates in "ordinary" mode: the Today's No Driving Day: usual weekday and Saturday restrictions, without exceptional extensions. However, even on days without an emergency, official reports have frequently rated the air quality as "bad" or "acceptable/moderate" in a large number of monitoring stations.
A start to 2026 with more contingencies than all of 2025
The start of 2026 has set off alarm bells in the Mexican capitalIn just a few months, an environmental emergency has been declared in Mexico City. six times, already exceeding the five activations recorded throughout 2025.
This increase reveals the structural conditions that favor the accumulation of pollutants. They not only persist, but seem to intensifyPart of the problem lies in the geographical configuration itself: Mexico City is located in a valley at about 2.200 meters altitude and surrounded by mountains, which complicates the dispersion of the pollutants.
In practice, emissions from traffic, industry, and fuel combustion They tend to get trapped in the basinWhen several days of adverse weather conditions occur consecutively, polluted air accumulates rapidly until it reaches the thresholds that force the activation of the contingency plan.
The data aligns with the diagnoses of international organizations. Recent reports on air quality in Latin America Mexico is among the countries with the worst levels of pollution. fine particles PM2.5with concentrations around 3,5 times higher than the levels recommended by the World Health Organization. Although in the capital the pollutant that triggers the air quality alert is usually ozone, the underlying high concentration of particulate matter reveals a chronic problem.
Hoy No Circula: how the program works on days without an emergency
To curb traffic emissions, Mexico City and more than 40 municipalities of the State of Mexico They apply the program No Circulation Today, which limits the circulation of vehicles in accordance with the color of the sticker, the license plate ending, and the type of verification hologram.
On ordinary working days, without a declared contingency, the scheme establishes that, of 5 to 00 pmCertain vehicles must be kept out of circulation both in the 16 boroughs of Mexico City as in metropolitan municipalities where the rule applies, including the Mexico's valley and areas like Toluca or Tianguistenco.
An example of this typical operation was seen in Thursday 5 of March of 2026, when CAMe reported that There was no active environmental contingency Therefore, the program was operating in its standard mode. That day, the restriction applied to vehicles with holograms 1 and 2, green rubber and plates with endings 1 and 2, in addition to a large part of the cars with foreign license plates that circulated in the metropolitan area.
Something similar happened on moons 2 de marzo, with specific limitations for vehicles with Yellow rubberized coating and plate termination 5 and 6as well as for foreign cars that are considered equivalent to the hologram 2No state of emergency was declared that day either, so The Double No Driving Today program was not activated.
Fines, exemptions and particularities of the Double No Driving Day
The program includes a series of Exceptions for less polluting or essential vehiclesThe following are exempt: electric and hybrid carsas well as those that carry holograms 00 and 0Also excluded from the restriction are public transport and emergency vehicles, which can circulate without time or day restrictions.
In contrast, cars with hologram 1 and 2 They are the most affected, especially if Phase 1 of the contingency plan is activated. In those episodes, the following measures come into effect: Double No Circulation Today, which expands the restricted license plates and stickers and may even involve, on a rotating basis, certain vehicles with 0 and 00 holograms to reinforce the reduction of emissions.
Failure to comply with the regulations comes at a high cost: those who violate the program in Mexico City may face financial penalties ranging from 20 to 200 times the Unit of Measurement and Update (UMA)which translates into fines that can exceed 23.000 Mexican pesos, in addition to towing the vehicle to the impound lot.
The situation is especially delicate for vehicles with license plates from other states without a verification hologram, which are treated in practice as if they had a hologram 2. Without a document that proves their exemption (such as the Tourist Pass), They cannot circulate on restricted days and times and they risk similar penalties to those imposed on local vehicles.
Weekends, Saturdays, and days with poor air quality but without an emergency
The restrictions become more complicated on weekends. Saturday, March 7, 2026For example, the authorities maintained the Saturday No Driving Today in normal mode, without additional contingency measures. During that first Saturday of the month, vehicles were not allowed to circulate. vehicles with hologram 2 and cars with hologram 1 and odd license plate ending (1, 3, 5, 7 and 9), in addition to foreign vehicles without local verification.
Meanwhile, the Mexico City Environment Secretariat reported poor air quality, posing a health riskalthough still below the threshold that would have triggered a declaration of contingency. This situation illustrates a recurring reality: there are days with worrying pollution levels in which a contingency phase is not formally activated, but in which similar precautions are recommended.
On Sundays the program changes its logic: under normal conditions, the The "Hoy No Circula" program is suspended.However, if the contingency is activated, the following may also apply: Double Sunday No Driving Day, with a rotating scheme that affects all vehicles with hologram 2 and, according to the latest activation, to different hologram groups 1, 0 and 00 depending on the license plate ending and the color of the sticker.
A recent case was the 8 March 2026 Sunday, when, despite the fact that several municipalities in the Valley of Mexico registered "bad" or "acceptable/moderate" air quality, The contingency plan and the Double No Driving Day program were not activated.The Air and Health Index rated the situation as "bad" in areas such as Cuautitlán, Tultitlán, Nezahualcóyotl, Merced or Miguel Hidalgo, while other stations remained at moderate values.
Continuous air monitoring and health recommendations
Behind every decision regarding contingencies and traffic restrictions lies a network of atmospheric monitoring stations distributed throughout the metropolis. The Mexico City Atmospheric Monitoring Directorate operates 16 stations in the capitalwhile the State of Mexico has 13 additional stations that complete the regional coverage.
With this data, the authorities publish hourly reports on the air quality and the intensity of ultraviolet raysIn one of the recent reports, issued to the 15:00 PM on March 2ndThe Air and Health Index classified air quality as "bad" and "high" risk for those who engage in outdoor activities, especially sensitive groups.
Meanwhile, the index of UV radiation reached level 5, associated with the recommendation of Use sunscreen, a hat or cap, and sunglasses with UV protection. to minimize damage from prolonged sun exposure. These types of messages have become routine for many residents, who check the air quality almost as frequently as the weather forecast.
The CAMe and the Mexico City government emphasize several key recommendations when air quality is poor or an emergency is declared: Avoid strenuous outdoor exercise between 13:00 PM and 19:00 PMpostpone civic, sporting, and cultural events abroad, and No smoking, especially in enclosed spacesThe goal is to reduce both the inhalation of pollutants and the additional generation of emissions at the most critical times.
Impact on health and the role of traffic in pollution
The effects of this situation on the population are significant. Data from the National Institute of Public Health estimate that Air pollution is behind thousands of premature deaths each year In Mexico, there has been a significant increase in respiratory and cardiovascular diseases associated with peaks in poor air quality.
Children, the elderly, and patients with pre-existing conditions are the most vulnerable, but the entire population is affected by continued exposure to ozone and fine particles (PM2.5)which can reach the bloodstream and contribute to chronic health problems.
Among the sources of pollution, the Vehicular traffic stands out as the main culprit in the capitalIt is estimated that more than 6,4 million cars in Mexico CityThis is in addition to millions of daily commutes from surrounding municipalities. The increase in the number of vehicles, especially motorcycles and private cars, is linked to the lack of efficient and attractive public transport alternatives.
This relationship between congestion and pollution was one of the central themes of the forum. “Traffic Congestion in the Mexico City Metropolitan Area: The Problem We Stopped Discussing”where the CAMe management stressed that chronic traffic congestion is not only a matter of mobility, but also a public health and urban model problem that no longer meets current needs.
Debate on fundamental solutions: public transport, teleworking and urban policies
Beyond short-term measures such as No Circulation TodaySpecialists and authorities agree that the solution lies in transform the mobility model and the urban structureThey argue that traffic congestion is a symptom of a system where Public transport fails to consolidate itself as a backbone and millions of people depend on private cars for transportation.
In this context, proposals have emerged ranging from the comprehensive improvement of public transport to the Introduction of legal changes to promote teleworking in episodes of high pollution. An initiative presented in the legislative arena proposes to reform the Federal Labor Law so that he remote work should be mandatory during environmental contingency days in Mexico City, with the aim of reducing travel and emissions during peak times.
The need for Update the Hoy No Circula program based on recent evidenceReviewing which types of vehicles should be more restricted, how to better integrate motorcycles, and how to coordinate measures among all entities that make up the metropolitan region.
For European cities that are making progress in implementing low emission zones, urban tolls or temporary restrictions during smog episodesThe experience of Mexico City offers several lessons: the importance of having robust monitoring networks, clear protocols for activating and deactivating measuresand above all an approach that combines immediate actions with structural transformations in mobility and urban planning.
The succession of poor air quality episodes, the increase in air quality alerts in 2026, and the heavy reliance on private cars show that Mexico City faces a complex challenge that cannot be solved with temporary restrictions alone. Between closed valleys, heavy traffic, and a public transportation system that still suffers from shortcomings, the The environmental emergency in Mexico City has become a constant reminder of the urgent need to rethink how we move around and how large cities are built., a debate that is also beginning to resonate strongly in many European cities.
