Contingencia Ambiental in Mexico City (CDMX)

The “Contingencia Ambiental” (Environmental Contingency) in Mexico City (CDMX) is a series of measures implemented when air pollution reaches hazardous levels. It’s designed to protect the health of residents, especially vulnerable groups like children, the elderly, and those with respiratory illnesses.

What Triggers a Contingencia Ambiental?

The environmental contingency is declared when air quality reaches specific thresholds for ozone (O₃) or particulate matter (PM_2.5 and PM₁₀). These thresholds are defined by the Índice de Calidad del Aire (Air Quality Index). When these pollutants reach dangerous concentrations, indicating a significant risk to public health, the authorities activate the contingency.

Levels of Contingency

There are different levels of contingency, each with progressively stricter measures:

• Fase I (Phase I): Declared when ozone or PM_2.5 levels reach a high concentration, posing a significant health risk.
• Fase II (Phase II): Activated when pollution levels reach even more dangerous concentrations, indicating a very high risk to public health. This phase involves stricter measures than Phase I.

Measures Taken During a Contingencia Ambiental

Once a contingency is declared, a range of actions are implemented to reduce pollution and protect public health. These measures can include:

• Hoy No Circula (Today Doesn’t Circulate) Extension: This program restricts vehicle circulation based on license plate numbers. During a contingency, the restrictions are typically extended to include more vehicles, potentially affecting vehicles that would normally be exempt. Older vehicles and those without catalytic converters are often targeted.
• Industrial Restrictions: Industries are required to reduce emissions, often by curtailing operations or using cleaner fuels.
• Construction Activity Restrictions: Construction and demolition activities that generate dust and pollutants are often suspended.
• Suspension of Certain Activities: Activities that contribute to air pollution, such as burning tires or open-air barbecues, are prohibited.
• School Closures: In extreme cases, schools may be closed to protect children from exposure to high levels of pollution.
• Recommendations to the Public: Residents are advised to stay indoors, avoid strenuous outdoor activities, and use public transportation. People with respiratory problems are urged to take extra precautions.

Why is the Contingencia Ambiental Necessary?

Mexico City, due to its geography, high population density, and industrial activity, is prone to air pollution. The contingency plan is a vital tool for mitigating the immediate health risks associated with high pollution levels and encouraging long-term improvements in air quality. By temporarily reducing emissions, the contingency aims to prevent severe health consequences and protect the well-being of the city’s inhabitants.

Staying Informed

During a Contingencia Ambiental, it is essential to stay informed about the specific measures in place and the air quality situation. Official sources, such as the Secretaría del Medio Ambiente (SEDEMA) and the Sistema de Monitoreo Atmosférico (Atmospheric Monitoring System), provide up-to-date information and recommendations.