I have seen rats at many of my favourite hawker centres like Ghim Moh, Bedok Blk 216, Beauty World, Commonwealth Drive, Holland Drive, Bukit Timah, ABC Hawker Centre, Hong Lim, People's Park etc. They seem to be everywhere in Sg these days.
New York City has 8 million residents that produce enough food waste to feed 5 times that number of rats. S'pore has more than 6 million people living in an area smaller than NY. Imagine how many rodents we have coming out every night to feast on leftovers/food products at hawker centres, food courts, restaurants and supermarkets.