CCNY maintains a strict drug policy that ensures anyone caught with illegal substances will be severely penalized—expulsion is possible. However, the incidence of drug use on campus is extremely rare. Most students are commuters, so taking drugs and drinking alcohol on campus is not a big interest. New York City is a large place, and drug use does happen, however it is mostly isolated from campus.
Security is everywhere, and police are vigilant, which keeps City free of common college vices. ID cards are required to enter dorms and some campus buildings, and while some may see this as a hassle, it helps ensure safety from common crimes. It's important to keep in mind that since this is a commuter school, campus life isn't highly controlled.