"More than 50 million people in 15 member States of the United Nation Economic Commission for Europe (UNECE) live in informal settlements ... This study provides a general overview of the phenomenon of informal settlements in the UNECE region and identifies policy responses to address these [economic and social] challenges. Emphasis is given to practices that can facilitate access to affordable land and housing and improve the livelihoods of residents in informal settlements, and in general to strategies that stand to better the physical, social, economic and environmental situation of informal settlements." (Quoted from paper)