The GOSB inner roads are sweeped and washed periodically. Also, due to the fact that the rain water gulleys and sand arresters are filled with precipitations every once in a while, these areas are cleaned periodically, and the gulleys within the area which are blocked and the rain water, wastewater gulleys and tunnels within the firm are opened up with skittles. The water in the rainwater drainages and sand arresters are checked, and if any pollution is detected, these waters are sampled and analysed.