I dont know, but i have these days low RPM and also low CPC.

I went through a few pages in the Ad Review centre, and blocked most of the ads. The RPM came back up pretty quickly after that.
Adsense isn't nearly as clever as we give it credit for.

@glitterball, are you sure that's not a fluctuation? removing ads lowers the competition and lowers the CPC. Did your CTR jump as soon as you removed the bad ads? Also, what are your criteria for disabling ads? Will try to replicate on my account as well

I removed all of the ads that were in Russian (it's an English website aimed at a mainly UK audience), were for stupid downloads, and ads aimed at markets that are not related to the website. I left all of the ads that were related to the same industry as the website. After 3 days of garbage, within two hours of blocking the ads, I was seeing relevant ads again and people actually clicking the ads (which they hadn't done for 3 days).

@glitterball did you have a long list of blocked ads in the previous account?

Not really, about 9 pages (c.90 ads) built up over time. I don't see any overlap with the ads that I blocked in the new account.

I changed over from a personal Adsense account to a business account a few years ago. Earnings and other metrics slumped for 7-10 days then slowly recovered. Just speculation but I suspect there's a degree of trust that accumulates with accounts that has to be 're-earned'.

I also changed my AdSense account a few days ago. Dropped for me too. Any idea when it could be recovered?

I removed all of the ads that were in Russian

There might be something to look at in this statement. When I started seeing wrong-language-ads in the Ad Review Center, I thought it was just Google mistargeting. But then I looked at my logs, and noticed I'd been getting (unusual and unaccountable) traffic from these countries - so the ads were displaying because some traffic was coming from these countries. Once I blocked some of them (people in Russia and and China don't really need to be viewing my state-oriented event sites) I stopped seeing those ads in the Ad Review Center.

TLDR - If you are seeing ads in the wrong languages for Review, check your traffic patterns.

I went through a few pages in the Ad Review centre

I set this up as a recurring item in my to-do list ... after X days review XX pages of ads. I included a link to the Ad Review center so it's just a click away.

It's rare that I review ads all the way to the end of the list, but this reminder makes sure that I at least check a regular sample.

There might be something to look at in this statement. When I started seeing wrong-language-ads in the Ad Review Center, I thought it was just Google mistargeting. But then I looked at my logs, and noticed I'd been getting (unusual and unaccountable) traffic from these countries - so the ads were displaying because some traffic was coming from these countries. Once I blocked some of them (people in Russia and and China don't really need to be viewing my state-oriented event sites) I stopped seeing those ads in the Ad Review Center.

TLDR - If you are seeing ads in the wrong languages for Review, check your traffic patterns.

I'm sure there's something in that, but I was seeing ads in Russian here too (and I don't speak Russian).