I want to use infinite scrolling in my website and I have three Google AdSense ad units on a page. If I use infinite scrolling the ads will also come with next page. But as per Google AdSense we can only have 3 ads per page. So will it go against Google AdSense policies?
It's certainly against the policies to display a 4th ad or more with infinite scroll. It souldn't be, as it just replicates legitimate pagination functionality, but they probably don't want to open the door to abuse so we'll have to just take it as it is.
It may also be against the policies if you don't fully display all 3 from the beginning but only add [some of] them with the infinite scroll, but that depends on the exact tech used and is more open to interpretation. However, this would be mostly useless - having the ads show before the infinite scroll starts will surely bring in more revenue.