Under the National Recycling Program, recycling bags were distributed to households and recycling bins placed in residential areas for households to store and recycle their recyclable wastes. In 2007, some 6000 public recycling bins have been placed at locations with high human traffic, and this number is still growing. Previously under this program, one recycling bin was placed every 5 HDB blocks. In 2011, the Singapore government enhanced this scheme to provide one recycling bin for every HDB block. This is an effort to remove the physical and structural barrier, or affordances, of recycling. Availability of recycling bins increases the convenience and thus likelihood of recycling behaviors.