How do i write a complaint letter about pollution in the ocean?

Start off with an attention grabber like; "Each morning as you go to the ocean you see plastic laying on the beach, fish rising to the surface due to the toxic liquids we allow to be put into the ocean. Paper, bottles, glass, and much more is destroying our once beautiful body of water. Are you going to do something about it?"

Then just explain what can be done. What needs to stop. Give facts and figures that you find off of a trusted site.