Picture of the day ("No" Signs") picture from phone

I see a prohibition sign at a hawker centre.It disallows pets,bicycles,littering and smoking. I think the reason why this sign is created is to maintain hygiene at a food centre (Pets and littering sign). Bicycles are restricted as to not pose a threat to pedestrians having their meal. Smoking is also prohibited so that people can have cleaner air while they consume their food.What if this sign does not exist ?Will the hygiene be very bad that it causes people to fall ill due to littering ?