Slowing Death is the disease of a website, the gradual banishment from the index.
When indexing / crawling a website, Google and other search engines recognize whether the content of this page is already known. If this is the case, your page will be devalued until you are removed from the index.
- Too similar content on news or shopping pages (article descriptions)
- Several URL parameters lead to the same content e.g. www.beispiel.de/?id=1&cat=2 www.beispiel.de/?cat=2&id=1
- several web addresses point to your page without 301 header redirect
- ZoneFiles of your site are configured incorrectly
robot.txt and .htaccess file
In these two files, search engines are instructed how and whether the page should be included in the index. If these files are configured incorrectly, your page will be included in the index incorrectly or not at all.
It should mean about 1.5 years of banishment from the Google index if the page is "sick" with slowing death. Slowing death is permanent and inevitably leads to exclusion, regardless of whether you set up redirects afterwards or not.