Is ablution (wudu') required for every prayer, or for involuntary flatulence? And is it permissible for someone afflicted with involuntary discharge of waste and flatulence to lead the prayer?

The fundamental principle is that ritual purity from minor and major impurities (hadath and khabath) is a condition for the validity of prayer. Therefore, one who carries impurities must remove or clean them before each prayer. The majority opinion is that the prayer of one who carries impurities is null and void absolutely, unless there is extreme hardship in removing them for every prayer, in which case it is excused. As for one with a continuous impurity (such as urinary incontinence or continuous flatulence), he must perform ablution (wudu') for each prayer. Scholars differ on the ruling regarding the imamate (leading prayer) of one with an excuse for those who do not have an excuse: some believe that his imamate is not valid except for those like him, because he has violated a pillar of prayer. Others believe in the validity of his imamate, but prefer that he not lead healthy individuals in prayer to avoid scholarly disagreement.