It looks as if it is always crying. It is actually adjusting its body’s fluid levels by eliminating excess.
It prefers arid environments. It leaks water from its eyes to adjust its body’s fluid levels.
It prefers an arid atmosphere. It leaks water that looks like tears when adjusting its moisture level.
In order to adjust the level of fluids in its body, it exudes water from its eyes. This makes it appear to be crying.
It does not deal well with water, so it lives in dry locales. Since its surroundings tend to lack greenery, it stands out noticeably.
— Pokédex entries (via PokeAPI)