My schools were all like that. "Kids aren't paying attention to our standardized-test preparation studies! Perhaps we should make schools more like bleak prisons, and force people to spend the bulk of their formative years there! That will certainly result in a more capable general populace."

My HS in central NJ had neither windows in the classrooms, nor WALLS. It was designed like a giant open office bullpen thing and classes were supposed to congregate in vaguely defined areas. By the time I got there in the early 90s, they had already erected borders everywhere out of movable chalkboards, so you basically got a traditional classroom layout but with noise pollution from all the other classes going on nearby. Great job all around. (Though I suppose from the CO2 standpoint we were probably doing better than most!)

The walls were part of a new teaching fad. I lived in a city that tried it out in one school. Each floor was an open plan for the classrooms. This one elementary school was their trial.

The teachers had a love/hate relationship with this plan.

Sounds like HHS. I was there in the 00s and the borders were these "permanent" accordion wall things

In many countries forcing people to stay in a room with no windows would be illegal, and for good reason.

My school was like that. I always heard it was in response to the 1970's energy crisis - windows are bad insulators.