Though the country as a whole has been rocked by narco violence, Mexico City has long been considered among the safest parts of Mexico. The U.S. State Department currently has no travel advisory in effect for Mexico City, though it cautions against traveling to the metropolitan area’s eastern fringe; check travel.state.gov for updated information.
Mexico City’s well-publicized kidnappings have generally targeted the Mexican power elite; the average tourist isn’t likely to be a victim of this type of crime. Authorities have been cracking down on taxi robberies, but policing an estimated 100,000 cabs is no easy feat. The first rule of Mexico City is never hail a taxi on the street, from a tourist attraction, or with your debit card in your pocket. Choose the sitio (stationed) cabs that operate out of stands or cabs called for by hotel or restaurant staff, or use apps such as Yaxi and Uber. The government has phased out the city’s once-iconic VW Beetle taxis since four-door vehicles are seen as a safer option (the driver cannot access backseat passengers as easily). Avoid any two-door taxis still in service.
It’s a good idea to avoid public transportation late at night. When taking the metro, note that the forward-most subway car is typically reserved for women and children only (though this rule is not always enforced or observed).
The Zócalo has undergone major changes, including rigorous trash pickup, a ban (sadly) on vendors and street food in the core, lots of guards, and in some places, security cameras. Major tourist areas are generally safe, but petty theft is pervasive. Pickpockets are brazen and unbelievably skilled. Recognize that Mexico City is formal, so things like big cameras, backpacks, shorts, and sandals will make you stand out.