When wudu becomes invalid?

Wudu, or ablution, becomes invalid under several circumstances, including the act of relieving oneself (urination or defecation), passing gas, deep sleep, or loss of consciousness. Additionally, if any part of the body that must be washed during wudu becomes impure, or if one touches a member of the opposite sex with desire, wudu is also rendered invalid. It is essential for Muslims to renew their wudu before performing prayers or other acts of worship.