Why does leaving a charged insulator in moist conditions help to discharge it?

Question

To discharge the charged insulator slowly, leave it in moist conditions.The water vapour in the air causes the excess charges on the insulator to leak away slowly.

Answer 1

Although we think of the air as being non conductive, it does conduct to a very minor degree. The more moisture it contains, the better it becomes as a conductor. This permits charges to find objects of a different charge, and dissipate. Relative humidity of around 50 percent and above make it difficult to build a static charge.

Answer 2

moist environment drastically changes the coefficient of permittivity of the medium. thats y