area cigarettes danger direction environment health health risk no smoking no smoking in this area sign not allowed pollution prohibition sign unhealthy warning black circle communicating communication denied directing directional directive informing no parking not permitted parking permission denied prohibited red reflective road sign street sign traffic traffic flow verge white access denied denying access denying entry forbidden multi-lingual protected protection restricted restricted area secure security serious stop alert appreciated appropriate-behavior appropriate-behaviour health-risk no-smoking not-allowed not-permitted permission-denied symbols thanks no right turn black and white canine control controlled denial dog dogs-prohibited exception lead leash pets rules appropriate behavior appropriate behaviour care chinese dangers english no diving rain rain-drops risk risks signs swimmers swimming water wet advice be-careful beware blue careful caution concern conditions directions garden lookout raindrops visitors warning-sign black-&-white gray grey greyscale clean clean-up cleanliness doggy-do droppings excrement excreta hygiene mess messy pickup poo prepared responsible sanitation waste