The key question to be asked with respect to indicators is, "So what?" - a short version of three questions - (a) So what is happening? (b) So what impact does it have on me? (c) So what do I do? Answering these three questions requires indicators that illustrate conditions and trends, causes, links between human influences and natural processes, ecological, economic and health effects, and implications for planning and policy etc. What are the stresses on the environment due to human activity, the resulting condition or state of the environment, and the policy response to correct undesirable situations?