Cities are important consumers of resources and producers of waste derived from the lifestyle and daily needs of their citizens, which is why they are considered the main actors responsible for the environmental impacts related to anthropogenic activities. The quantification of these impacts is fundamental for the definition of sustainable cities. In this work, a material flow accounting study combined with the Life Cycle Assessment approach is conducted for the municipality of Madrid, the most populated city of Spain. The findings of this study allow performing a sustainability diagnosis of a large city such as Madrid, identifying energy needs, food consumption and manufactures as environmental hotspots. In addressing the comprehensive analysis of available data, important constraints arise, such as access to data. To this end, not only the development of precise estimation tools to quantify these flows, but also greater transparency of data sources, are fundamental elements in the study of the sustainability indicators proposed in this paper. Therefore, the success of any proposed sustainability strategy depends on the involvement of policy-makers and citizens in the objectives and measures set, as well as on the access to information and training on sustainability as fundamental action line driven by local government.

城市是重要的资源消耗者，也是因市民的生活方式和日常需求而产生的废物的产生者，因此，人们将城市视为与人为活动有关的环境影响的主要参与者。这些影响的量化对于定义可持续城市至关重要。在这项工作中，针对人口稠密的西班牙马德里市进行了物料流会计研究，并结合了生命周期评估方法。这项研究的结果可以对马德里等大城市进行可持续性诊断，确定能源需求，食品消耗和制成品是环境热点。在对可用数据进行全面分析时，出现了重要的限制，例如对数据的访问。为此，本文中提出的可持续性指标研究的基本要素不仅是开发精确的估计工具以量化这些流量，而且还提高了数据源的透明度。因此，任何拟议的可持续发展战略的成功与否，都取决于决策者和公民是否参与制定的目标和措施，以及能否获得有关可持续发展的信息和培训，这是地方政府推动的基本行动方针。