Other rat-control exercises
About 180 rats were caught over five days near Bukit Batok MRT station in December 2014.
The situation was believed to be caused by animal feeders who left food for stray dogs nearby.
A video showing rats scurrying around a slope near the MRT station went viral.
It took pest controllers three weeks to wipe out the infestation.
More than 50 rats were caught in an extermination exercise in Bedok South after residents reported a rise in rodent numbers across blocks 69 to 72 in April last year.
The National Environment Agency found 16 burrows at Block 70 and rat droppings in a bin centre and two food outlets, which were later given warnings.