For travelers considering environmental concerns, Friends of the Earth. org releases an annual report card of the overall environmental and human health impacts of each cruise line. Each were graded on their overall environmental footprint. Separate scores for sewage treatment, air pollution reduction, and water quality compliance were combined into an overall letter grade.
- Disney Cruise Lines was the only line to receive and "A" overall due to high water compliance and treatment marks. The A+ ship was the Disney Wonder. Holland America. Norwegian, and Princess Cruises were all close behind, each earning overall "B" ratings. Celebrity received a C+ overall due to air pollution concerns, but it was the only cruise line listed with four ships that received individual A grades (Constellation, Infinity, Millennium, and Summit).