“Città Metropolitana Spugna (sponge)” is implementing 90 climate impact mitigation interventions in public areas (parking lots, squares, roads and green areas) thanks to the use of Nature Based Solution (NBS). The project is realized together with 32 Municipalities in the metropolitan area and thanks to the investment of funds from the PNRR – Integrated Urban Plans (PUI).  

“Sponge cities” are engineering projects based on sustainable urban drainage (SUDS) works and nature-based processes, as the most effective tool to reduce floods, conserve water for droughts and reduce water pollution. The Metropolitan City thus aims to reduce the vulnerability of natural and socio-economic systems and strengthen the resilience capacity of the territory, characterized by high levels of waterproofing and high urban density. 

In support of the 90 projects of the PUI Spugna, the Metropolitan City provides a service for the implementation of cultural and economic promotion activities with the aim to: 

• Promote knowledge and foster understanding of the importance of a sustainable management of stormwater 

• Overcome potential conflicts and worries and support the acceptance of the interventions 

• Ensure efficiency and long-term maintenance of the interventions 

• Expand the impact of the PUI Spugna at a metropolitan scale in a replicability perspective   

The cultural and economic promotion service was assigned, in November 2024, to a temporary grouping of companies involving, together with Poliedra, Ambiente Italia srl (leader), Politecnico Milano – DASTU, Cooperativa Sociale Eliante and Iridra srl. 

 

The role of Poliedra 

The promotion service proposes a set of territorial animation activities in the municipalities of the interventions that foresee the engagement of economic, social and local community stakeholders through dissemination activities, training activities, public events and citizen engagement initiatives, the storytelling of the application of the DNSH principle to the interventions, and so on. The promotion initiatives will be diversified according to the different public spaces and the user population of each area, the prevalent NBS and the type of intervention. 

Poliedra is responsible for designing, leading and facilitating all the citizens engagement activities, in agreement with Città Metropolitana, CAP and the Municipalities involved, as well as with the other partners of the RTI. 

In detail, since June 2025, Poliedra has been carrying out: 

• exploratory itineraries and routes (such as the bike ride at the intervention sites in Canegrate) 

• co-design workshop with a view to the future management of the areas subject to intervention, along with public celebration events at the redeveloped site/space (for example, on the occasion of the inauguration of Piazza degli Artigiani in Turbigo) 

• Awareness-raising days dedicated to the schools involved in the interventions (such as the case of the M.L. King School in Pieve Emanuele or the Amphitheatre on Via delle Acacie in Cesano Boscone) 

• play-based activities through the “City of Sponges – Goose Game”, engaging even the youngest participants to discover the City of Sponges and its projects while having fun, and online gamification through the photo contest “The Sponge City of the Future”, which invites participants to build a future vision of the territory by creating AI-generated images.