Discrimination against "untouchable castes" afflicts nearly quarter of a billion people around the world. Although many people assume "untouchability" is restricted to communities with a Hindu background, this dehumanizing tradition is found in cultures as different as Japan and Nigeria. In an article this week in a leading Nigerian newspaper, Leo Igwe explained how the International Humanist and Ethical Union (IHEU) is working to overcome "untouchability" in Nigeria, despite the government’s official denial of the problem. The full article is available here on the website of the Guardian (Nigeria).