Roads are swept to schedules in order to ensure that they comply with the standards set under the Environmental Protection Act. The actual frequency of cleansing varies according to the degree of littering that normally occurs, as follows :- the three pedestrian precincts are cleaned 4 times a day, 7 days per week; district shops once a day; areas of heavy usage e.g. schools - weekly; residential areas once every 2 weeks or once every 4 weeks.