The littering issue is pretty serious in Marsiling estate. I rented a room there for 6months. There was this dangeous zone which I walked past daily. Everyday, there would be some thing thrown down from an unit's kitchen window, curry gravy, macdonald left over, toilet papers,etc. It was a horrible sight.
I stayed at 5 different estates last time. Other matured estates, which I previously stayed also have this littering problem, except for Bishan. New towns like Sengkang and Punggol are definitely cleaner.
When moving to a matured estate, such sights are part of the package. Bopian have to close 1 eye. Anyway we are free to move to other estate after MOP 5 years.
1 important thing to take note is that crime rates in Marsiling and Woodlands are relatively higher than other estates. So when you are walking home very late, you need to be extra careful. It will be safer to take a feeder bus instead of walk from the interchange. There's a bus-stop right beside our blocks.