It needs to be said, because I wish this existed in my country:
General Littering Offences
This category includes common littering offences such as discarding small waste items like tissue paper, food wrappers, cigarette butts, or plastic packaging in public areas. Individuals found guilty of such acts may face the following penalties:
First-time offenders: Fine of up to $2,000
Second-time offenders: Fine of up to $4,000
Having clean streets would be so nice.
Also,
The median income (inclusive of employer CPF contributions) in Singapore is [...] US$4,442/month or US$53,304/year. https://smartwealth.sg/average-income-salary-singapore/
So the police needs to catch like two or three people doing it in a month to earn the wage. Easily pays for itself so policing it is very worth it to the state.