It is known that increased humidity helps discharge a charged body. I was wondering what is the molecular mechanism of that process. It is not clear to me why increased number of well separated uncharged water molecules in the air will help the process of discharge. Does the polarity of water molecules help? How? Does self ionization play any role, although the chance of two water molecules interacting with each other in air is so low? I am having difficulty with this question specially because liquid pure water is not a good conductor. Am I correct in assuming that increased humidity cause higher discharge rate? Thank you for your answer.