Since the dawn of time, people have been moving from one place to another in search of more opportunities and a better life. These migrations have continued until present times and have even increased. The complexity of migration has also increased due to the formation of nations with clearly defined borders. It has been argued that increased migration as a whole has great benefits for humanity. However, this population movement has caused the promotion of phenomena such as overpopulation, ethnic factionalism and social stratification, which have had adverse social, economic and political impacts. This essay will demonstrate the negative social, economic and political effects on host countries resulting from increasing mass migration from developing to developed regions in the 21st century. Increasing migration in the 21st century has had a negative effect on the societies of receiving countries. in many ways. This has caused overpopulation, which creates many harmful social phenomena such as increased unemployment due to many competitors and limited functions. Duncan, R. states (2008) that this produces limited income for the poor, which leads to increased crime. As a result, the community will become unsafe. Furthermore, unemployment leads to the spread of bad habits such as smoking, alcohol consumption and drug addiction, which lead to mental and physical illnesses. As a result, the health conditions of society will deteriorate. Koehlmoos, TP, Uddin, MJ, Ashraf, A & Rashid, M state (2009) that as in the case of Dhaka, the capital of Bangladesh receives 320,000 immigrants per year. This leads to overpopulation in this city. This has left 3.4 million people homeless. This caused the increase...... middle of document ......cs & Logistics, vol. 5, no.3, pp.311, accessed 12/18/2009, ProQuest database. Shannon A Brown, 2002, “Resource Wars: The New Landscape of Global Conflict / Iraq and the International Oil System: Why America Went to War in the Gulf”, The Journal of Military History, vol. 66, no.4, pp.1265-1267, accessed 12/18/2009, ProQuest database. Blanchflower, D 2007, “Fear, unemployment and migration”, Bank of England. Quarterly Bulletin, vol.47, no.4, pp592-599, accessed 04/12/2009, ProQuest database. Anonymous, ? 2001, “News: ethnic conflicts”, International Journal of World Peace, vol. 18, no.1, pp.97-98, accessed 12/18/2009, ProQuest database. James J James, Italo Subbarao, William L Lanier 2008, “Improving the Art and Science of Disaster Medicine and Public Health Preparedness”, Mayo Clinic Proceedings, vol. 83, n°5, pp.559-562, consulted on 12/18/2009, ProQuest database.