According to the study, the most cocaine is consumed in the English city of Middlesbrough.Image: shutterstock
Through wastewater analysis, conclusions can be drawn about drug consumption in different cities. A European comparison now shows that Switzerland is at the forefront when it comes to coke and pot smoking. Ketamine use is also increasing.
Mar 19, 2026, 5:47 p.mMar 19, 2026, 5:47 p.m
Cocaine and ketamine consumption is increasing in Europe, as a study of wastewater levels in 115 cities by the European Drug Authority (EUDA) shows. The ketamine values in particular are particularly striking: compared to the previous year, the amount measured increased by 41 percent. According to the study, the fast-acting painkiller and anesthetic is particularly popular in Belgium, Germany and the Netherlands.
Cocaine consumption among Europeans has also increased, by 22 percent compared to wastewater levels in 2024. Since the study collects data via the global scientific network SCORE, it also includes figures from non-EU countries.
Swiss cities in the top 10
With Zurich and Geneva, there are two Swiss representatives among the ten cities in which, according to the study, the most coke is consumed. While the values in Zurich have remained stable over the last four years, they have increased by around 40 percent in Geneva. This means that the westernmost city in Switzerland is replacing Zurich for the first time as the place with the highest cocaine residues in wastewater in Switzerland.
The study also shows that in no other city in Europe has such a high proportion of the cannabis breakdown product THC-COOH been measured as in Geneva. Cannabis consumers in French-speaking Switzerland are leaving even Amsterdam behind and are ensuring this year’s European record.
European comparison is a snapshot
The study by the European Drug Authority was carried out for the first time in 2011 and aims to use standardized water analyzes to compare the consumption of illegal drugs within European cities. However, due to the data collection, this is a snapshot. The wastewater values are collected at all locations simultaneously within a single week. The numbers determined are relative values; they indicate how many nanograms were measured on average per day per 1,000 inhabitants.
Meanwhile, studies by the Swiss Federal Water Research Institute EAWAG are more suitable for more precise observation of trends and developments regarding drug consumption in Switzerland. In contrast to the European study, the wastewater samples at the Swiss institute are taken and examined every 13 days.
Swiss samples confirm trend
The recently published figures from EAWAG show that there is a similar trend in the consumption of cocaine and ketamine in Switzerland as in international comparison. According to the national study, the consumption of crack is also increasing, while the residues of crystal meth and cannabis detected in wastewater, as Watson reported a month agoare declining. (July)