How to tell the owner tactfully not to throw rubbish upstairs?

Don't throw rubbish casually. The copy is as follows:

In order to maintain the public health and everyone's health in this community and keep the community clean and tidy, the owners are requested not to throw garbage upstairs at will, but to put the garbage in the designated area or trash can.

Please don't pile up sundries, litter and spit upstairs to make our home better.