# Implementation of the 3-30-300 Green City Concept: Warsaw Case Study
## 1 Introduction
They categorize green spaces into several types, with the maximum distance to them varying depending on size, quality, and type. Although this approach seems comprehensive, understanding all aspects of the analysis may be difficult and time-consuming due to its complexity and detailed guidelines. Another example is the research presented by [PERSON] et al. [15], which aimed to examine the availability of green spaces in 299 EU cities. The results indicate that cities in southern Europe have fewer accessible green areas due to low forest cover, while cities in northern Europe have more. This issue is further complicated by the uneven distribution of green spaces in many metropolises. [PERSON] et al. [16] focused on Mexico City as an example of a city with significant social and locational inequalities. Their analysis revealed an asymmetry in the distribution of green spaces. It was also noted that less affluent municipalities have less access to green areas, which might lead to various health issues for residents. The authors highlighted the need for a more equitable distribution of green spaces and the necessity to integrate them into urban planning, especially in currently marginalized areas. This problem has also been raised in other studies relating to other cities, e.g., Chicago, where it would seem that such problems are not experienced by residents [17]. Subsequent studies have addressed the topics of diminishing green spaces and deteriorating quality of urban life [18]. They have used satellite imagery and data and GIS tools [19] to develop, among others, a spatial accessibility model that assesses the accessibility of green spaces from different points in a city. The results have shown that the accessibility of green spaces decreases as one moves away from the city center. In the central parts of Fuzhou, residents have better access to green spaces, while on the outskirts of the city, accessibility is limited. Its spatial equity analysis further revealed significant inequalities in access to green spaces. In some districts of the city, green spaces are over-concentrated, while other areas, especially on the outskirts, suffer from a shortage. This problem has also been recognized at a high level of decision-making in the Eu-European Union, resulting in a strategy called \"European Biodiversity Strategy for 2030\" [20]. The main element of this strategy is, first of all, broadly defined nature conservation in the European Union. We are talking about the expansion of protected areas, where legal protection will be extended to 30% of land and sea, of which 10% will be strictly protected (including primary forests). The strategy also sets a target of planting three billion new trees by 2030 and allocating 20 billion euros a year to fund biodiversity conservation activities. Such measures will undoubtedly have a positive impact on the well-being of the population and help to halt environmental degradation. It is also worth noting that this topic is addressed in the agenda entitled Transforming Our World: 2030 Agenda for Sustainable Development [21], which was adopted by 193 UN Member States at the General Assembly on 25 September 2015. This agenda consists of 17 goals and 169 related tasks. A particularly relevant goal from the perspective of our work is Goal 11 entitled \"Make cities and human settlements inclusive, safe, resilient and sustainable\". This goal has two important points relevant to our work, namely that all countries that have signed this document have committed that \"By 2030, enhance inclusive and sustainable urbanization and capacity for participatory, integrated and sustainable human settlement planning and management in all countries\" and \"By 2030, provide universal access to safe, inclusive and accessible, green and public spaces, in particular for women and children, older persons and persons with disabilities\". The above review of research on the issue of green cities shows that the studies focus mainly on the impact of greenery on residents' health.