The terms “light”, “mild”, “ultra-light”, “extra-light”, “extra-mild” are misleading. They've been part of a strategy to reassure smokers, and there's been a perception created by tobacco industry marketing that these are significantly less harmful than “regular” cigarettes. Unfortunately, many people have switched to these brands instead of quitting altogether.
There is now an international recognition that these terms are deceptive. It's cited in the international tobacco treaty, the Framework Convention on Tobacco Control. At least 50 countries have prohibited these terms specifically, and three major companies in Canada and a number of smaller ones, following an investigation by the Competition Bureau, have entered legally enforceable settlements to have these terms removed from their brands. These regulations will put this into a regulatory form to cover those companies that are not yet subject to such agreements.