MyAnimeList has a composite metric of popularity of anime, which includes the total sum of all people who have listed an anime as any of Watching, Completed, On-Hold, Dropped, or Plan to Watch on the site.
If any seasonal anime (listed as new in any of Winter 2024, Spring 2024, Summer 2024, or Fall 2024) has reached 1 million people by the end of the 2024, Japan time, this market will resolve YES. If no anime has reached 1 million people, this market will resolve no.
For reference, no anime achieved this in 2023. The closest were (numbers at the time of market creation):
Jujutsu Kaisen 2nd Season: 853k
Kimetsu no Yaiba Swordsmith Village Arc: 780k
Oshi no Ko: 753k
Jigokuraku: 646k
Vinland Saga Season 2: 578k
Sousou no Frieren: 558k
For 2022 anime, this was achieved by 5 different anime: Chainsaw Man (1.5M), Spy X Family (1.5M), Kimetsu no Yaiba Yuukaku-hen (1.4M), Shingeki no Kyojin Final Season Part 2 (1.3M), and Sono Bisque Doll (1.0M).
This question will not take into any TV anime that is continuing on from previous years. It will also not take into account any Movies, OVAs, or Specials.