Status of the Informal Sector in Sustainability of Urban Economy (Case study: Tabriz City)

Introduction  
The informal economy is the diversified set of economic activities, enterprises, jobs, and workers that are not regulated or protected by the state. The concept is originally applied to self-employment in small unregistered enterprises. It has been expanded to include wage employment in unprotected jobs. The present research is an attempt to realize the location of informal economic section in the sustainability of Tabriz megalopolis. This phenomenon involves many variation and widespread development. Importance and specific location of the informal economic section in urban economy is so intensive that could never be ignored. The informal economic section has attracted numerous people of Tabriz megalopolis and plays an important role in the economy of that. Conventional approaches to urban development generally are of one-way model and are dependent on political conditions and economic purposes. Nevertheless, since the late decade of twentieth century, this subject has taken systematic and multiracial condition to itself.
Methodology 
This study as an applied development research involves descriptive and case study methods using documentary-library and field techniques. The tools for gathering data are including questionnaires, observation, interview, statistic documents of Iran statistics center. The information acquired from analytic maps is provided in Geographical Information System (GIS). The study is a descriptive- analytic research in method. Thus, the quantitative models and techniques like X² test and V cramer are employed in GIS, Arcview and SPSS. The statistic population of this research involves the people working in informal economic section of Tabriz megalopolis. Through an accidental sampling method, we selected 390 samples, including 282 men and 108 women. The present investigation is analyzed by the use of descriptive-inferential statistic methods in SPSS.
Results and discussion 
The Tabriz megalopolis is an example of urban development models which is entirely changed due to variation of urban planning in recent decades. This investigation attempts to evaluate the economic roots of this problem based on urban sustainability views to provide a proper context for better judgement in urban planning. The results of this research indicated that most of the businessmen in informal economic section of Tabriz megalopolis are men (72.3 percent) and married people (82.3 percent).
The activities of informal economic section in Tabriz megalopolis are clothes sellers (11.5 percent), fruit sellers (10.8 percent), and building workers (8.5 percent), carpet knitters (5.4 percent). The most important kinds of occupations in informal section of this city are salesmanship, domestic service giving people, scientific, educational, artistic services, transportation and agriculture. The businessmen in informal section of Tabriz are mostly unqualified people in education. Average age of these people is 42years old. Most of the people working in this section are rural – urban immigrants and their inhabitants are mostly in margins of Tabriz city. The most important reason for the people to enter to this informal section is the lack of enough capital and specialty to qualify better opportunities.   These businessmen are mostly in Abrasan (5.9 percent), Seilab (4.6 percent),  Maralan (4.6 percent), and Abbasi (4.4 percent) areas. The most important occupational problems of this group is the inadequacy of capital, lack of specialty and qualification, and lack of fixed location for performing economic activities. Most of the working people in this section (31.4 percent) have revenues between 400 to 600 US dollars. This shows that the people are below poverty line and affected by intensive poverty. 
Conclusion  
Geographical distribution of informal economic section in Tabriz megalopolis is not uniform. Most of the people working in this informal section are rural-urban immigrants in the city. The occupational variety in informal economic section in Tabriz megalopolis is more intensive for men than Women.