Industrial symbiosis seeks to decrease ecological impact of firms within a regional industrial system through exchanges of by-products and waste, and utility sharing. Industrial parks that seek to develop symbiotic linkages are referred to as Sustainable Industrial Clusters (SICs) in this study. Policy makers and scholars have recognized the need to establish policies for the development of SICs. However, the implementation of policies for SIC is still an under-researched part of policy processes. To improve understanding of the dynamics of long-term and non-linear policy implementation, this study elaborates the issue of policy durability. Policy durability refers to the established degrees of stability, coherence, and integrity of policy as time passes, and also the ability to adapt to changing conditions. It reflects continuous governmental efforts to solve public issues. Our focus on policy durability is based on the observation that SIC policies need to be sustained for many years, but in practice they are sometimes introduced and implemented for a short time and then dissolved, which can lead to discontinuities of local SIC practices, and further undermine what has been already achieved. Policy durability is an important quality of public policy in general and of SIC policy in particular. The thesis elaborates this underestimated condition for the development of SICs. The research question is: How does policy become durable in search for effective facilitation of the development of SICs? To answer the question, two relationships are addressed in this study: 1) the process-dynamics contributing to durable policies, and 2) the effects of durable policies on the development of SICs.