"Ground Written Advertisements" now becomes a big problems for our modern cities,especially for some coastal cities such like Shenzhen.

Contents of these ads are things like "selling certificates","hypothecation","private detective","dun sb. for payment for you(in violent way)",etc.And these texts can be seen almost everywhere in the city,sidewalk,bus stop,crossover,zebra crossing,etc.

These Ads are hard to clean.Once you spent much time to clean them,it'll be easy to write again during midnight.Even you arrest those guys who wrote these,what could you do to them?They're just "employees",even you send them to prison,there'll be new one to continue this work soon.