A recent study has ranked Mumbai as the most traffic-congested city in the world for the second straight year, and Delhi at fourth place. How was this determined, and what do the findings say of traffic across the world?

The study
The findings are part of the Traffic Index 2018 published by TomTom, an Amsterdam-based company that offers traffic solutions, uses location technology to collect traffic information, and has been publishing city rankings for eight years. The latest index ranks 403 cities across 56 countries, including 13 new cities.

The measure
For this study, congestion has been defined in terms of the additional time taken to reach a destination as opposed to when the road would have been clear of traffic. Mumbai’s 2018 congestion level of 65%, therefore, means that the extra travel time is 65% more than an average trip would take during uncongested conditions. For Delhi, by the same yardstick, the extra travel time is 58% more.

Most congested cities

Around the world
Nearly 75% of the cities part of the 2018 index had increased or stable congestion levels between 2017 and 2018, with only 90 cities showing measurable decreases, states the report.