Why does ice appear on the inside of a house on a bus or tram on the windows in severe frosts?

In severe frosts inside public transport, the windows have a temperature below zero, because most often the windows are made of one layer of glass, which, due to thermal conductivity, is equally cold outside and inside. In the cabin, due to the breathing of people, the air humidity is always very high. The air near the glass is very cooled and can no longer retain such an amount of moisture. Moisture drops out and freezes. To prevent ice from forming, you can put double-glazed windows instead of single glasses.