High floor Litter Bug

[summer_snow]

Hi.
I am staying in this HDB for 5 years, since around 6 months ago, there is this "neighbour" who will on and off throw food out of the window and make a big mess in the area, we can find Cha Siew Rice on our aircon, Lunchboxes down from high floor, noodles etc.
Though it does not happened "very often" yet it is very annoying when things happen. Any idea what can I do? Goodness know what they are going to throw one day???!!!
I have no idea which floor is it, do I have to be sure which is the level that throw the rubbish then I can lodge a complain?

[monica]

Look up from d window,if above have a air con than it not from upstair.but it some where near by you,maybe just 1 or 2 storey.cant be upper than that

[calltcnneg]

Call the town council and if they can't help you, contact the national environment agency.