Wow uhh... what a doozy. I don't see this thread becoming controversial at all...</s>
1. Get rid of Abrahamic monotheism at the source: Religion as an institution is pretty inertial and hard to get rid of (I mean Hinduism has been around in one form or another for close to 4000 years). It stands to reason that since Christianity and Islam are the two biggest world religions, and they both stem from Judaism, so if you get rid of Judaism and/or early Christianity, you get rid of the two largest world religions from OTL. One POD I can think of would be for the early Christian gospels to never be officially written down, instead simply remaining as oral traditions. Then again, very few people back then were literate anyways, so I'm not sure that them not being written down would be that much of a factor. If you have the Romans be more thorough in their genocide of the Jews during the Great Jewish Revolt in the 60s and 70s CE (just wanna be clear that I'm not anti-semitic and genocide is always bad). The ancient Romans clearly had no qualms with genocide, as they regularly slaughtered, deported, or enslaved entire ethnic groups, so it's possible I suppose. But of course that wouldn't get rid of religion in general, just the three primary monotheistic religions that exist today. The POD might be 609 BCE where the revolt against the Neo-Assyrians fails, or some point in the 500s BCE where the Neo-Babylonian Empire lasts longer, and in either of those TLs Judaism may be eventually snuffed out. However Judaism, Christianity, or Islam would obviously be replaced ITTL by something, but the more vague and non-prosthelitizing pagan religions of the ancient near East may eventually fade into obscurity with whatever "Renaissance" or "Enlightenment" happens ITTL, leaving only atheism. Obviously there's nothing ITTL preventing other prosthelitizing religions from emerging and becoming dominant in the world. Of course, this TL would do nothing to address hinduism, buddhism, confucianism, or any other eastern religions, which would still be alive and well if the POD is as late as the 60s CE (or even the 500s BCE). I don't know enough about the religious history of Asia and Africa to comment meaningfully on any of those.
2. Evangelical atheism: You might could have a POD in the 1600s-1800s where any of the philosophers of the Enlightenment rationalize that "spreading atheism" is a moral good and atheism catches on as an ideological trend in the West. I have my doubts on that succeeding because Christianity and Islam are both prosthelitizing religions and would necessarily resist any such efforts very fiercely, and they would have been well-established for well over 1000 years by this point.
3. No religion from the beginning: Alternatively, you could have a POD millions of years in the past where humans evolve to become less prone to correlating natural phenomena with contrived ideas of gods, preventing religion from ever developing as a cultural phenomenon. Of course, there's no consensus on what factors actually cause religions to develop, so I can't give a singular POD for that, since the psychological foundation of religiosity isn't fully understood. Obviously I'm coming from a nonreligious POV, and not trying to offend any religious people on the site, so please don't take any of the above as a personal attack. Another possible source might be the Indo-Europeans never migrate anywhere, the butterflies from that might eliminate hinduism and the abrahamic faiths, leaving only premedieval paganism and maybe a less diverse set of eastern religions
4. 1984 happens and the government actively kills all religion: That one's pretty self-explanatory. Basically any totalitarian government takes over the world and achieves such complete control over language and thought that they're able to snuff out religion completely.
5. Just give it time: One last suggestion might be no POD at all. Irreligion is on the rise in the West and is presumably correlated with standard of living (some of the least religious countries are Japan, South Korea, Norway, and Sweden, all of which have a very high standard of living), so as human living conditions gradually rise all around the world, maybe we'll all become nonreligious eventually, we just haven't given all religions enough time to fizzle out yet. Maybe at the end of history, everyone will be wealthy and we'll understand the universe fully enough that religion becomes totally unnecessary as an explanatory phenomenon, I have my doubts though, religion is nothing if not stubborn.
One last thing, how the heck do you spell "prosthelitizing"? I know I'm spelling it wrong but I can't figure out the correct spelling for the life of me.