Explain what is termed as little sins in the letter that the mayor received

I do not see the phrase "little sin" used in the text. In Scene One, however, the Judge tells everyone they to get their affairs in order. The Warden of Charities should look to the way the hospital is presented. The watchmen in the courthouse have been raising geese in the building, the Judge always has clothes hanging in his chambers, and his district assessor always smells bad. The Mayor takes bribes, and the teachers in the schools are radicals. These are all considered infractions.... things that need to be fixed before the arrival of the Inspector.