These are the 20 most congested cities in the world

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Traffic in Rio de Janeiro, Brazil.

• The transportation data firm INRIX Research released on Tuesday its annual rankings of the most congested cities in the world.
• Cities were ranked based on delays caused by congestion, adjusted for each city's population.
• Moscow was named the most congested city in the world for the second year in a row, and Europe had more cities in the top 20 than any other continent.

The transportation data firm INRIX Research released on Tuesday its annual rankings of the most congested cities in the world.

The company measured the amount of time lost per capita in 2018 due to the difference between traffic at the busiest and least busy commuting times each day. Cities were ranked based on delays caused by congestion, adjusted for each city's population.

Moscow was named the most congested city in the world for the second year in a row, and Europe had more cities in the top-20 than any other continent.

These are the most congested cities in the world.