In 2018, 42 of the world's 50 most violent cities were in Latin America. Four were in the US, with another in Puerto Rico.

The region is the world's most violent, excluding war zones, with bloodshed driven by organized crime and exacerbated by chronic instability, poverty, and corruption.

In 2018, Latin America retained the ignominious distinction of being home to most of the cities on Mexico's Citizens' Council for Public Security's annual ranking of the world's most violent cities, released on Tuesday.

Of the 50 cities on the list, 42 are in Latin America. Fifteen were in Mexico, 14 in Brazil, and six in Venezuela. Two Colombian cities were on the list, as were two Honduran cities, and El Salvador, Guatemala, and Jamaica all had one.

Four US cities were listed: St. Louis, Baltimore, Detroit, and New Orleans. San Juan, the capital of Puerto Rico, is also on the list. (Puerto Rico is a US territory but not a state.)

Read last year's list: These were the 50 most violent cities in the world in 2017

The list is limited to cities with more than 300,000 people and doesn't include cities in war zones, such as Syria or Ukraine. The council said that when assessing cities, it sought to include "localities that form a unique urban system, clearly distinguishable from others, independent of the geographic-administrative divisions inside the countries."

Violence in Latin America is in large part driven by drug trafficking and organized crime. Insecurity is also exacerbated by political instability, poverty, and poor economic conditions. Corruption, abuses by officials, and impunity also facilitate crime.

Mexico has seen profound increases in deadly violence in recent years, driven in large part by the fragmentation of criminal groups. This year Mexico displaced Brazil as the country with the most cities on the list, despite Brazil having some 80 million more residents. One of Mexico's most popular tourist cities, Los Cabos, topped the list last year but is not on it this year, which the council attributes to one criminal group winning control of the area.

See the 2016 rankings: The 50 most violent cities in the world in 2016

Incomplete data also challenges the council's tabulations, particularly in Venezuela, where the government has in the past not released homicide data, and where other estimates, such as those by newspapers, are incomplete or inconsistent.

Venezuela's "growing inability to count its dead" underscores the very serious crises it faces, the council states.

Here's the top 50: