We had this same problem in 30's, 40's and 50's people would toss trash out of cars all across the USA (for the life of me I cannot understand why).
Unfortunately we had to put laws into place to really make a difference. You are fined a good deal if you were caught littering this really helped people to take responsibility.
Hopefully your government will use the poor citizens in this project and pay them well so they can earn a living in the process.
Also, American TV would show this short commercial after all of the TV Stations would shut down for the night
(We didn't have cable back then and only 3 TV stations)
and this one:
it really raised conscience levels-
All the Best