The antonyms for the phrase "wast in operation" are active, functioning, working, operational, productive, efficient, and effective. These words imply a sense of activity, movement, and progress, which stand in stark contrast to the sense of stagnancy and inactivity conveyed by the original phrase. When something is "wast in operation," it suggests that it is either broken or no longer in use, which can be detrimental to its intended purpose. In contrast, words like efficient and effective suggest that something is both useful and responsive to the needs of its users, making it an essential component of any well-functioning system.