Just hours after the clampdown started, the Letten area - which last summer attracted up to 4,000 drug users - was eerily empty of its usual habitants.
"I don't know what I'm going to do," said Armin, a pale-faced addict. "I feel ill, I urgently need a fix. I don't know where my friends are," he muttered as he wandered forlornly in a street near the old Letten railway station.
Throughout the city, addicts and dealers kept a low-profile for fear of being detained. Those with enough money had stocked up on heroin or cocaine on Monday. Workmen moved in to clear up syringe wrappers, discarded needles and condoms lying in the filth behind the barricaded entrance in grim testimony to the past.
The authorities decided to close Letten because of growing violence and protests from local residents and businesses. Van-loads of police specially trained to disperse the addicts were instead kept busy with the crowds of journalists and television teams that descended to record the event.
"There are more journalists than junkies," one drug dealer said shortly before the midnight deadline on Monday.
During the day, 25 addicts were taken to a temporary holding centre from where they would be sent home, according to Robert Neukomm, the police chief. He said 17 dealers were arrested in three co-ordinated raids, codenamed "Operation Drumbeat", involving 300 police.
Residents of the district near Letten had been told to lock their homes and challenge anyone suspicious. However, there was also a palpable sense of relief that the local nightmare might be ending.
All dealers will be arrested and foreigners without residence permits deported. However, prisons intended for the dealers are rapidly filling up, according to officials.
Although drug use is illegal, there are no plans to imprison addicts. Those who are from the Zurich area will be offered treatment to help them to kick the habit. Care facilities in the city - which has the most progressive drug policy in the country - have been increased.
However, the Association of Drug Specialists warned that the closure of Letten would merely force addicts elsewhere. The organisation's president, Vigeli Venzin, said prices would rise and quality would fall as the drug scene was driven underground.
Mr Venzin said addicts' health would suffer as a result, and that there would be more temptation to share needles, thus increasing the risk of Aids.
The Swiss Interior Minister has convened a conference for Saturday in an effort to develop a new national policy. The government has already given the go-ahead for 1,000 addicts to be given heroin under strict medical supervision.
Previous attempts to stamp out drug dealing in Zurich failed. Three years ago police closed a "needle park" next to the main train station in the heart of Zurich. That merely scattered addicts into nearby residential areas before they regrouped in Letten.Reuse content