Wool

In a post-apocalyptic future, people have lived for generations in a silo dug 144 stories down into the ground. The air outside is toxic and society inside the silo lives under many restrictions. Food is scarce, and society is heavily regulated. 

The only view of the outside world is through sensors controlled by the IT department. Nobody goes outside except criminals who are punished for a crime. The camera lenses get dirty and need regular cleaning, and those who are expelled from the silo always clean the camera lenses. 

Three years before the story starts, the wife of the protagonoist Holton voluntarily left the silo, because she thought that the IT department was tricking the residents and that the world outside was actually not toxic.

Wool was self-published in 2011 as a stand-alone short story, and published in 2012 as the first section of a novel titled Wool Omnibus. The sequel Shift tells the story of how the silos came to be, and Dust completes the trilogy.