Generally, Singapore is pretty clean and wants to remain that status.
However, when you step into the HDB heartlands, you will find that some residents do litter, especially floor near to the letterbox area are full of leaflets. Also irresponsible people sticking advertisements all over the place, resulting walls being dirtied when the sticky paper ads are peeled off.
Dirty Letterbox Area
I hope everyone should maintain our neighborhoods clean and comfortable.