This audit checks that no more than three ads are initially loaded below the fold. The area below the fold only becomes visible after a user scrolls down. Ads in this area are less likely to be seen by users, so loading an excessive number of them can lower viewability rates and decrease page performance.
Lazily load ads that are positioned below the fold. Lazy loading is a technique that prevents ads outside of the viewport from being requested and rendered until they are close to being scrolled into view. See the GPT lazy loading sample for an example implementation.