Ambulance (Rettungswagen)
144
Police (Polizei)
117
Fire (Feuerwehr)
118
The number 112 can be dialled in most of Europe to reach emergency services. It can be called from any telephone (landline, pay phone or mobile cellular phone) for free. EasyExpat's FAQ on emergency numbers can help you find the emergency numbers around the world.
Zurich, like most cities in Switzerland, is very safe. Violent crime is extremely unusual and the most common crime is petty thievery and pickpockets. Public transport is completely safe to use at all hours of operation. The only area that might offer an issue is along the lakefront where drunks occasionally congregate and fight.
The police force has two departments.
Stadtpolizei - Responsible for the city area
Kantonspolizei - Responsible for the whole region.
Police are generally helpful, but also approach "suspicious" persons in order to check their papers. At least carry a photocopy of your passport to prove your identity and avoid trouble.