Introduction 
Increasing informal settlements without complying with legal frameworks will have adverse effects on the quality of the environment. The decrease in the quality of the environment of these types of settlements indicates a more unpleasant environment and also indicates an unlivable or livable settlement at a low level. As a result, Tabriz metropolis is no exception to this rule, and more than 500 thousand people live in these informal settlements. In this research, the northern informal settlements of Tabriz city were selected, which include 5 districts of Silab, Malazinal, Ahmedabad, Idalu, and Abbasi. These areas, which have seen an increase in house-building activities, are located in the northern part of Tabriz city. The activities of house building and development of facilities have drawn the attention of builders and opportunistic dealers to the region. And it has led to the development of illegal housing by private activists in a surprising way in the northern area of Tabriz. Assessment of livability in informal settlements created in terms of constructions with illegal land divisions has not been fully and accurately investigated before. The research in this field is limited and has only been investigated in the form of exploitation of activities, policies and effects in Iranian cities. In fact, illegal constructions and land separation have dominated the housing development processes in the suburban areas of Iranian cities, especially Tabriz. As a result, this research was carried out with the aim of developing livability criteria and measuring the livability of informal settlements with constructions and the separation of illegal lands and a vital role in creating a bridge between informal settlements developed with construction and separation of illegal lands with the concept livable settlements will play a role and will finally facilitate the informal urban housing markets as a tool to control the informal development of housing and informal settlements and its adverse effects on the quality of the environment so that citizens can have access to livable settlements in the future to be.
Materials and Methods
This study used primary research supplemented with secondary research as the main source of data collection. In order to identify informal settlements created by illegal constructions and separations in the northern region of Tabriz, several research techniques were used, such as exploratory interviews with land brokers, preliminary explorations with Google Earth of informal settlements, field observations, and authentic interviews with the municipality of the region. Ten cities of Tabriz were used. After determining the key locations in this field, preliminary researches are conducted in the form of interviews with selected experts to achieve the first goal, which is to develop livability criteria, and questionnaire-based interviews with the resident population to achieve the goal. Second, the livability of the informal settlements developed by dealers’ illegal constructions and separations of the city was assessed in the northern area of Tabriz city. The analytical method used to achieve the objectives of the study includes two analytical stages, which are categorized into stage one (quantitative content analysis) and stage two (distance analysis and importance-performance analysis (IPA). The work process in which each analytical stage plays a role will play is described in the following sections.
Findings
From the experts’ questionnaire analysis, eight main criteria and 28 sub-criteria of livability in the settlements created by informal land dividers were obtained. These criteria arise not only from the input variable, but also from several recommendations and adjustments based on experts’ inputs. These eight main criteria become the main priority for performance improvement, as described below; 1) distance to entertainment centers; 2) access to medical services; 3) the state of asphalt of local roads; 4) the condition of drainage channels; 5) the density of buildings; 6) distance to parks; 7) Financial ability to buy land for housing, and; 8) Access to workplaces around the residence, according to the eight mentioned criteria that affect the improvement of the livability of informal settlements in the northern zone of Tabriz, it can be concluded that improving the quality of life in these areas requires serious attention to urban infrastructure, welfare, and economic services. Criteria such as the distance to recreational centers, access to medical services, and the condition of asphalt roads show the importance of meeting the daily needs and welfare of the residents of these areas. Improving these indicators can have a significant effect on increasing satisfaction and reducing people’s daily problems. In addition, criteria such as the condition of drainage channels and the density of buildings emphasize environmental and safety issues. The poor condition in these areas not only threatens the residents’ health but also leads to infrastructural problems that will cost the city a lot in the long run. Improving these aspects requires long-term investments and systematic urban planning. Two other important criteria, including the financial ability to buy land and access to the workplace, refer to economic and social factors. The economic ability of the residents to buy land and easy access to the workplace are among the key factors in reducing poverty and increasing the sustainability of life in these areas. Without addressing these issues, other efforts to improve physical and infrastructural conditions may have limited effects.
Conclusion
This research shows that to improve livability in informal settlements, it is necessary to simultaneously focus on urban infrastructure, public services, and residents’ economic power. On the other hand, the research concludes that policymakers and urban planners should take into account these criteria and develop comprehensive solutions in accordance with the social and economic realities of these areas. Finally, this research, as a practical guide to improve the conditions of informal settlements, can help city officials allocate resources and measures more efficiently by prioritizing problems and needs and, as a result, improve urban performance and increase the quality of life of its residents. Regions to help.