Are you familiar with Agoraphobia?
I know it is a fear of open spaces
More specifically, Agoraphobia is considered an anxiety disorder. Basically, the person with this sees the environment as unsafe. 
Is it any environment, or specific environments?
Open spaces that you previously mentioned trigger these individuals. So this can literally include any place - even malls or restaurants. They end up having panic attacks more often than not in these scenarios. 
Are these feelings caused by a feeling of inferiority?
leave their homes.
Agoraphobia is believed to be due to a combination of genetic and environmental factors. The condition often runs in families, and stressful or traumatic events such as the death of a parent or being attacked may be a trigger. In the DSM-5 agoraphobia is classified as a phobia along with specific phobias and social phobia. Other conditions that can produce similar symptoms include separation anxiety, posttraumatic stress disorder, and major depressive disorder. Those affected are at higher risk of depression and substance use disorder.
Without treatment
Agoraphobia
Agoraphobia is an anxiety disorder characterized by symptoms of anxiety in situations where the person perceives their environment to be unsafe with no easy way to escape. These situations can include open spaces, public transit, shopping centers, or simply being outside their home. Being in these situations may result in a panic attack. The symptoms occur nearly every time the situation is encountered and last for more than six months. Those affected will go to great lengths to avoid these situations. In severe cases people may become completely unable to