No matter how much the MOE tries to tell Singaporeans that "every school is a good school", the fact remains that many parents stop at nothing to get their kids into what they perceive as the top primary schools in Singapore.
When there are too many students trying to get into a school, the school will run a ballot, which is basically a lottery. At this point, the only thing that can give your child an edge is if you live within 2km of the school. In fact, the nearer the school, the better your odds.
Source: https://www.asiaone.com/lifestyle/how-much-does-it-cost-live-near-top-primary-schools-singapore