In the centre is Earth and there are two drops on it. One drop in blue is to show water and the other one is green to show greenery. Together they define the environment. The four arrows revolve around it like a cycle to show the 4r's nescessary to preserve the environment.
The R is formed out of Recycle, Reuse and Reduce. The E is formed out of Refuse. Together it show's all the 4 R's with the focus on RE.