Which of the following vitiates Hajj?

Sexual intercourse during Hajj completely invalidates the pilgrimage. The pilgrim must complete that Hajj, then perform another Hajj the following year, and sacrifice an animal.

This is because Hajj requires complete spiritual focus and physical purity. Sexual relations break the state of ihram in the most serious way.

Other prohibited acts include hunting, cutting hair, and using perfume, but none are as serious as this.