Singapore has a 2% unemployment rate. That basically means everyone is working. Menial labor is resourced to the Filipino population who come to work in Singapore - the best destination for "greener pastures", i.e. higher salary. Sunday is a day-off on construction sites. It's a day for enjoying the city for those who are not working - MRT (public transportation), shopping malls and hawker food courts. I like the pronounced change of demographic of Singapore on Sundays - 'sunday best' seems to apply.