This refers to things that are done on earth. See how you translated this in [Ecclesiastes 1:3](../01/03.md). Alternate translation: "on the earth" (See: [[rc://en/ta/man/jit/figs-idiom]])
The author says that everything that people do is as useless as if they were trying to control the wind. Alternate translation: "are as useless as trying to control the wind" (See: [[rc://en/ta/man/jit/figs-metaphor]])