I think that it is necessary to celebrate Environment Day. By showing our support for the environment it will help spread awareness of the issues that are hurting the places that we live, work and play. By showing commercials that depict oil spills, over population, and the need to recycle brings the issues into people's homes. Making people aware is the sole purpose of Environment Day.
Holidays are about spending money which helps the economy. Environment Day doesn't celebrate anything, but it's an attempt by environmentalists to make us feel guilty for things we need to do just to survive. There can be awareness for the environment, but it can hardly be a holiday like Christmas or Thanksgiving.