The presence of circular economy and sustainability concepts in recent regional calls for proposals. An analysis on the proposals submitted by companies was presented. A relevant fact of this analysis was that most of the symbiosis proposals studied were included in the R&D Programmes, rather than in Innovation or Cooperation Programmes.

Industrial areas as a natural environment for industrial symbiosis: concentration of companies, availability of infrastructures and the possibility of an steady supply were considered the key factors for IS to appear in this environment.