Background The City Council of Soria, in the Spanish region of Castilla y León, has signed the Aalborg +10 Commitments, and is therefore working to implement this framework for sustainable urban development. Through its municipal budget, and with the support of additional instruments aimed at protecting the environment, the city is developing infrastructure for optimum waste management and environmentally-friendly transport systems. It is also promoting awareness and education on environmental issues. The Soria CO2Cero project (LIFE09 ENV/ES/000437) is contributing to these objectives by creating an environmental corridor crossing the city, which includes improved waste management approaches, and pedestrian and bicycle trails. However, the impact of public interventions depends to a large extent on the positive attitudes of citizens and local businesses. It is essential, therefore, that the local community is fully engaged in such measures from the outset. Objectives The main objective of the People CO2Cero project was to strengthen the engagement of the local community in efforts to improve the environmental performance of the city of Soria (population just over 39 000). At the same time, it aimed to link citizen mobilisation with economic objectives to create approaches that involved businesses in sustainable urban development and job creation. The project sought to move beyond existing ‘reactive’ approaches of citizen mobilisation toward a process where citizens led a bottom-up and proactive process of environmental improvement. It also encouraged financial institutions to implement innovative eco-investment products and private companies to participate in Corporate Social Responsibility processes. Furthermore, an additional aim was to create free-to-use software for eco-auditing, which could be used to monitor and evaluate CO2 emissions from everyday activities in households, public entities and businesses located in the eco-corridor. Results The People CO2Cero project successfully promoted citizen involvement in promoting sustainable urban development, developed eco-auditing software, and raised public awareness of environmental issues relating to energy and water use, recycling and transport. The City Council created a citizens’ network, to link the municipality and its people, tasked with implementing environmental actions, including eco-auditing, green acquisition and awareness-raising. A working group of 20 volunteer organisers was established. Also known as UEAs (Urban Environmental Agents) or ‘Territorial Guards’, these people were committed to work with the City Council to improve the urban environment in Soria. The UEAs were trained using courses developed by the project, and met regularly through these workshops and seminars, each of which focused on a particular environmental issue such as waste management, sustainable mobility, and energy efficiency. Eco-investments were promoted through the creation of an area for preferential eco-investment activities in Soria, which included the environmental corridor; the historic town centre, with its many old buildings; and the San Juan District, an economically-depressed area. The municipality drafted a document entitled ‘Delimitation of the area of preferential eco-investments in Soria’, which catalogued energy services companies in the area and proposed measures (e.g. grants, tax rebates and technical assistance) to be provided by the municipality. The plan to implement these actions was approved by the government board of the municipality, which has officially and legally committed to modify some ordinances to further the plan’s objectives in the area of preferential eco-investments. By the completion of the project, eco-investment had largely focussed on a district heating initiative involving a biomass power station. The People CO2Cero project therefore put in place a framework to help enterprises and banks promote investment in areas such as energy efficiency, while also promoting a green purchasing initiative. Further, the City Council organised an International seminar on best practices in financing eco investments within the framework of the Project. The beneficiary developed a methodology and a free-to-use online software tool, together with an associated eco auditing guidebook, so that eco-audits can be performed in the area of preferential investments. Eco-audits included assessments of energy and water consumption. A total of 60 eco-audits were conducted during the timeframe of the project, involving the collaboration of 16 companies and 39 households. Of these, 19 were conducted face-to-face, through the involvement of the citizens’ network of volunteers established by the project, and 36 conducted online, through the project’s website (co2cero.soria.es). Participants gained knowledge of, for example, saving energy and reducing CO2 emissions, and on the benefits of installing water saving devices. Project actions were accompanied by an extensive dissemination and communication campaign. This included the distribution of poster-leaflets and brochures, including ones with information about European Mobility Week and best practices for energy and water saving, and educational activities, including a course on sustainable gardening. The main achievement of the People CO2Cero project was to raise the environmental awareness of the citizenship of Soria: a step forward in the creation of a sustainable city. As a result, from 2008 to 3013, the amount of glass and packaging being recycled in the municipality increased; while the amount of waste disposed of in incorrect recycling bins decreased. Other achievements included in a new composting programme for households. The focus of the ‘After LIFE communication plan’ is to consolidate the Soria CO2Cero brand and to keep the UEA's team active as a link between the citizens and the municipality. This team will continue the eco-auditing programme and work to create new initiatives for environmental improvement. Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).