Index bloat is a state in which a website has a large number of pages in the search engine's index that have no value for the user or for the company. Typically, this involves pagination, filter combinations, internal search results, empty categories, date and author archives, and test and duplicate URLs. The consequence is diluted quality across the website as a whole, wasted crawl budget, and the search engine having a harder time working out which page is the main one for a given topic. You can spot it by comparing the number of indexed URLs with the number of pages the website should actually have. The solution is to decide on each type of URL: keep it and improve it, exclude it from indexing, merge it with another page, or remove it with a redirect. Do not do this in bulk without checking, or you will accidentally exclude pages that bring in traffic too.
See also: Crawl budget, Faceted navigation, Content cannibalisation.
