Development levies are essentially government charges that fund growth-related capital costs like childcare, fire facilities, police, emergency medical services and roads. Whenever a condo is built, new pipes, trees, even schools will be built around them to support the population. The developer passes a small amount of those costs on to the eventual owner of the condo.
An important part of your agreement is to set a cap on these levy charges so that you as a homeowner are not on the hook for too much.