The Bellagio process led to the Bellagio Declaration, a set of principles for how to ensure that any system for monitoring the transition to a circular economy captures all relevant aspects and involves all relevant parties. The work began as a collaboration between ISPRA in Italy and the European Environment Agency, guided by an advisory group encompassing EPA (Environmental Protection Agencies) Network representatives from Finland, Ireland, the Netherlands, Portugal and Slovakia.

The Bellagio Declaration was prepared by Italy's Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA) and the EEA, with a mandate from the Network of the Heads of Environmental Protection Agencies in Europe (EPA Network).