Major organisation in Singapore
The National Environment Agency (NEA) is the leading organisation in Singapore that oversees the cleaning 
of public areas to ensure that areas are hygienic and litter-free. NEA uses a 3-pronged approach to ensure the cleanliness of the streets and to maintain the reputation of Singapore being a clean and attractive city:
1. Cleaning of Public Areas
2. Public Education
3. Enforcement
More information of NEA: http://www.nea.gov.sg/public-health/public-cleanliness