After cannabis, cocaine is the most widely used illegal drug in Europe. ADVERTISEMENT ADVERTISEMENT The latest report by the European Union Drugs Agency (EUDA) gives a picture of where use might be more widespread, based on residual quantities found in wastewater. Spanish and Belgian cities collected the largest samples. Lleida, in western Catalonia, topped the continent's chart with 1,405 mg of cocaine found per 1,000 residents on average. Antwerp, in Belgium, is second (1,382), followed by