(Portland, OR) -- The City of Portland is advising restaurants with outdoor seating to make sure they're properly maintained. Plastics that are outside become hazy under exposure from the sun, vehicle exhaust, and other pollution making it more difficult to clean. Mold can also be an issue. Restaurants with outdoor seating need to have a storm drain and keep it clean from leaves. Restaurants can start applying now to renew their outdoor dining permits. New applications will be taken from May through October.