Pages Google will not index usually mean a quality problem
Deleting pages to shrink the site is not the fix, according to Google and SEO Glenn Gabe.
If Google has visited your pages but refuses to put them in search results, the usual reason is quality.
That is the message from Google's John Mueller, quoted by Barry Schwartz and by SEO Glenn Gabe. In Google Search Console (the free Google tool that shows how your site does in search), pages can get filed under "Crawled, currently not indexed" or "Discovered, currently not indexed". Crawled means Google came and read the page. Discovered means Google knows the page exists but has not read it. Neither one is in the index, so neither one can rank.
Mueller's line, as quoted by Glenn Gabe, is that this is "usually a sign that Google's quality systems are unconvinced about your site". Or, as he puts it, convinced in a way you do not want.
Deleting pages is not the shortcut
The other half of Mueller's comment matters more for anyone who has been told to prune their site. He says making the site smaller does not significantly raise its overall quality. So mass deleting old pages to improve some average is not the move being described here.
Glenn Gabe agrees it very well could be a quality issue if you have a lot of URLs sitting in those two buckets. He says the answer could be to significantly improve quality over time, and that this is what Google wants to see. In his words that can yield more URLs getting crawled and indexed.
He also adds a caveat worth keeping. It really depends on what you find in the reporting. A handful of unindexed pages is normal. Hundreds or thousands of them is a pattern.
What to do
Open Search Console, click Pages, and look at the rows labelled "Crawled, currently not indexed" and "Discovered, currently not indexed". Click into each one and read the actual list of URLs. If the pages are near duplicates of each other, thin pages with no real answer, or templates with one word swapped, that is the thing to fix.
Fixing it means making those pages genuinely better and doing it over time, not in one weekend. Google is looking for a sustained direction, not a single edit. If the unindexed list is short and the pages are ones you do not care about, you can leave them alone.
This is one Google employee explaining how the reporting usually lines up with quality systems. It is not an announcement of a change, and nothing has been updated. It is a read on what those two labels tend to mean when they pile up.
Just making the site smaller doesn't significantly raise the overall quality of the site.
the answer could be to *significantly* improve quality over time. That's what Google wants to see, which can yield more urls getting crawled and indexed.
Be the person who already knew
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