Shadowing of natural light by buildings
There is a growing body of evidence that man actually needs daylight, since the cycle of daylight somehow plays a vital role in the maintenance of the body's circadian rhythms. The change of light during the day is a fundamental constant by which the human body maintains its relationship to the environment. Thus, too much artificial light can create a rift between a person and his surroundings, and upset the human physiology. However, modern buildings are often designed with no concern for natural light, and depend almost entirely on artificial light. There are instances on record of people leaving jobs because of the lack of natural light.
Buildings which displace natural light as the major source of illumination are not appropriate or comfortable for human beings to live and work in. Any room suitable for habitation should have not merely one window, but two, on different sides. The building density and tallness of buildings in cities rarely allows this. Artificial lighting is also uniform lighting, which destroys the social nature of space and makes people feel disoriented. By contrast, pools of light are used to reinforce the social nature of space, as where a pool of light may irradiate a favourite armchair, or be suspended for intimate effect over a dining table.