Is it permissible for someone whose clothes have become soiled due to his work, and who wishes to pray in congregation, to pray at the back of the mosque, away from the rows, to avoid the worshippers being bothered by his smell?

One who works in a profession that causes his clothes to become dirty, yet they remain pure, should acquire a special garment for prayer, out of reverence for the ordinances of Allah. If his dirty clothes are pure and do not have an offensive odor or dirt that would transfer to those next to him, then he may pray in the row with the congregants. His prayer is valid, though disliked, if he prays alone behind the row without an excuse.