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Add a permanent 301 redirect from your /index page and point to your root domain (i.e. non /index pages).  - You need to do the redirect over canonical because it's a duplicate page/URL rather than a page with blocks of similar content. Update all mentions within your website that link to the /index page so that they only link to the non /index page. With CMS's you'll need to look where things get automatically added, like links in sitemap, footer, breadcrumbs, the 'home' link and sub-navigation.You may need a developer to remove them if not accessible via the CMS. Then your duplicate content issues will be gone.