In the 1940s, the New York City government, facing an influx of people to build ships for World War II, decided to regulate apartment rents, setting the maximum price landowners could charge from tenants. Seventy years later, New York City continues to face a shortage of housing; flats are often not renovated since landlords cannot charge more for a better-quality apartment, and a black market has emerged where the actual rent charged can easily be five times what is put on the lease. Some landlords even accept non-registered payments upfront to allow a person to move into a rent-controlled apartment.