Wet windows with mildew as result

I have a big problem.
I'm living in Japan now for around half a year and I realised that my window is nearly always wet despite the fact that I always ventilate my room. I already know about these one-layer windows... this stuff is so old that even my parents didn't experience it anymore...

So I have the problem that after today's cleaning I realised there was so much mildew that I got shocked. No wonder all Japanese have allergies if they live with this stuff!

So I have a question: How can I prevent the wndows from getting wet?!
Because after drying them with a towel they got wet again 10 minutes afterwards...

I don't want to get ill!!

You should move out of your house if you can. I can't imagine such a humid house in early spring.

Take care of yourself.

Find out the source of the moisture & fix the problem, from the kitchen, bathroom or leak from outside/upstairs? If the moisture is coming from within your apartment and regular airing/ventilation do not help, buy a dehumidifier which also dry your clothes in Tsuyu season..
Destroy any mold spore with chlorine but make sure to look behind any normally invisible places/spaces.