Close open basement windows

Hello,

I have the following problem:

I have a more or less open basement, which I now want to close. There are large basement windows, but they are ONLY closed with a grate, so no window! Therefore, dust, rain, animals, etc. all come into the basement.

Until now, I had large plexiglass sheets in front of the basement, but where I live there is ALWAYS very much wind and sun, and the plexiglass got damaged over time.

WHAT options do I still have to "close" the basement windows? It must, of course, be bright enough, so light should still come in.

Also: as cheap as possible, since it’s a rental house!!! So nothing expensive and permanent.

Thanks. max

I am a tenant but I am in Italy, where things are a bit different. I haven't actually rented the basement, so I can't expect the landlord to seal it.

Attached are two pictures of the basement windows.

Hi,
I had a similar problem with my house and then took [Jalousiegitter] as a solution, they let through little dust and no animals, but it still doesn't get musty because the air can circulate and enough light still comes through the slats.