Hoy No Circula

Hoy No Circula (literally in Spanish: "today [your car] does not circulate", known as No-drive days) is the name of an environmental program intended to improve the air quality of Mexico City.

A similar coordinated program operates within the State of México, which surrounds Mexico City on three sides.

The "Hoy no Circula" program was started in late 1989, and consisted of prohibiting the circulation of 20% of vehicles from Monday to Friday depending on the last digit of their license plates.

Hoy No Circula is coupled with an exhaust monitoring program, known as verificación in Spanish, whereby a car's pollutant emissions are analyzed every six months.

Class "0" (generally, cars less than 9 years old and meeting more stringent emissions requirements) are exempt from the Hoy no Circula program.

Class "2" vehicles (including all pre-1991 passenger cars) meet weaker emissions requirements, but are subject to both Hoy no Circula and an environmental contingency program.

Such vehicles are then not allowed on the road, and their owners are fined if the property tax hologram is absent after the expiration date.

Emergency services, solar or electric vehicles, government and school buses are also exempt.

Vehicles that are 30 years or older can apply for an auto antiguo (antique) license plate, that exempts them from emissions testing and hoy no circula restrictions.

This requires an inspection of the vehicle by local authorities and a large fee to be paid (currently around $1000 USD) in order to receive these plates.

Note that on certain holidays, the local authorities will permit, depending on environmental conditions, for any vehicle to circulate without restriction.

Automobiles registered in the states of Guanajuato, Hidalgo, México, Michoacán, Morelos, Puebla, Querétaro and Tlaxcala are not eligible for a "00" hologram sticker.

Such restrictions are often changed every six months and are related to the levels of ozone and particulate matter in the air, which are measured hourly.

One part of this program permits, without any special pass, for foreign-plated vehicles regardless of model year (those with plates from other than states in Mexico) to pass freely through the metropolitan area without regard to the Hoy No Circula program.