What is what episode is big mom defeated?

In the popular anime and manga series "One Piece," the episode in which Big Mom is defeated is Chapter 903. This event takes place during the "Whole Cake Island" arc, where the Straw Hat Pirates, led by Monkey D. Luffy, embark on a mission to rescue their crewmate, Sanji, from his arranged marriage to Charlotte Pudding by taking on the powerful Big Mom Pirates and their leader, the Yonko Big Mom herself.

After a fierce battle, Luffy manages to defeat Big Mom, leading to significant consequences for both parties involved. The defeat of Big Mom marks a turning point in the series and has lasting impacts on the ongoing story and the balance of power among the pirates in the world of One Piece.