socially - any area generally overcrowded, where the majority of residents have a lower than average education or income, as compared to the city as a whole, and affected by significantly higher than average crime rates or illegal activities as compared to the city as whole.

urbanistically - any neighborhood where at least 20% of residents do not have proper access to services such as electricity, water, sewer, garbage collection, mail delivery, health services, and easily accessible public transportation.

geographically - any neighborhood built on undeveloped land, and/or on hills' slopes, prone to sever damage during heavy rains.    

legally - any residential area where land and property ownership is generally not properly recorded through the official city channels or at city hall.