Why is Sulphur powder being sprinkled along the fence?

Yellow-coloured Sulphur powder is seen sprinkled on the ground along the perimeter of the fence of a school in Serangoon area. Do you know why? That is to prevent snakes from coming into the school compound. For those who don't believe, ask your parents or grandparents! I don't think it is being taught in the school Chemistry class. By the way, when sulphur is burnt, it produces Sulphur Dioxide which has a bleaching or whitening effect.