There are some of the regions in the world which has relatively more humidity as compared to the other regions. It is the introduction and development being going on, of utilizing this resource. Yes, the humidity can be used for the extracting the electricity from it. The basic is developed from the simple basic idea that whenever a piece of metal is kept in the humid environment. Then a charge is developed on the metal surface. The charge increases with the increase in the humidity.
Also, the amount of charge develop depends on other factors like type of metal, relative humidity, exposure time, surface area. However, efforts are made to utilize this resource more accurately. In future, we can expect more developments in this technology. Find some more information on this in the attached file.