Around here, when the authorities spray the swamps to deter mosquito borne
diseases, they use a larvicide. That way they can pinpoint the mosquitoes
without hurting beneficial insects. See if you can get hold of a mosquito
larvicide to spray the trees & other spots in the area that may contain
standing water. I gather Singapore is an extremely tight-run neatnik place.
Maybe you can enlist the government's help with some aerial spraying. I doubt
if you have the only apartment house in the region with a mosquito problem.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"A tree never hits an automobile except in self defense." - Woody Allen