It simply provides a bit of additional clarity and a bit of additional breadth in terms of the right. As I've provided in my written brief, these words have clear and widely accepted definitions. All three of these adjectives—“clean”, “healthy” and “sustainable”—have been used by different nations around the world in their articulation of the right to a healthy environment. As well, those adjectives have been in use by the United Nations in its work on human rights and the environment over the course of the past decade.
I feel that it just provides a consistent and clear articulation of what we are actually trying to protect in this case.