Cocaine use tends to be higher in western and southern European cities, according to the database of the European Monitoring Centre for Drugs and Drug Addiction.

As Statista's Anna Fleck reports, researchers analyzed the wastewater of 88 cities in 23 EU countries and Turkey for levels of a number of illicit drugs, including cocaine, MDMA and ketamine, in order to explore the drug-taking habits of their inhabitants.

They found that cities in Belgium, the Netherlands and Spain had the highest levels of cocaine in their water, while lower levels were found in most eastern European cities.

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The Flemish city of Antwerp had 1,722 milligrams detected per 1,000 people flowing through its drains per day in 2023, making it the city with the highest levels of cocaine in their wastewater of the sites included in the study.

Other cities with notably high concentrations were the port cities of Tarragona, Spain (1,464mg) and the Netherlands' Amsterdam (1,210), Leeuwarden (1,192mg) and Rotterdam (1,088mg).

According to the report, when looking at a number of cities outside of Europe, Brazil and the United States showed similar levels of cocaine use to the worst offending cities in Europe.