Filter AdSense ads displayed on your site

You can filter websites and ads from showing your site or AdSense for search results pages. To do so, sign in to your AdSense account at https://www.google.com/adsense and make the necessary changes on the Allow & block ads tab. Learn more about allowing and blocking ads in AdSense

Notes:

• Ads for websites that you add to your competitive ad filter list typically won't run on your pages.
• Filtering sites may decrease the number of ads that can appear on your pages and your potential earnings.
• You can add up to 200 sites to your filter list.
• The URLs you enter into your filter list can be the actual URL of the website or the URL that is displayed on the ad for that website.

Ad quality

Rest assured that ad quality on Google and publisher sites is a top priority:

• Review: Across the Google network, ads are reviewed through a combination of human and automated processes before appearing on publisher sites. The review process takes into account a variety of factors, including the quality of the ad and whether the ad is suitable for all audiences.
• Sensitive content filters: At times, certain ads may not be appropriate to run on all pages. For example, Google automatically filters out ads that would be inappropriate on a news page about a catastrophic event.

While our ad quality processes are highly effective, it isn't possible to guarantee that all content you deem objectionable will be prevented from appearing on your site.

SOURCE: support.google.com