Commentary: What will it take for Singapore residents to get serious about recycling?

However, a world full of sticks would be an unpleasant place. There is evidence that carrots can also effectively bring down the contamination rate.

A two-year recycling trial in Bishan and Sin Ming using “smart boxes” has a contamination rate of just 10 per cent – a significant difference from the 40 per cent average at the blue bins.

The smart boxes, operated by waste management company 800 Super, collects paper, plastic, aluminium, metal cans, old clothing and glass in separate bins. To use the boxes, residents must download an app and log in via a QR code. They are awarded points for recycling, which can be exchanged for supermarket vouchers.

While the vouchers are likely to be a draw for some people, this significant drop in contamination rate can perhaps also be attributed to a perceived reduction in contamination risk because of the controlled access to depositing items into the bins.

Yet another contributing factor might be the need to deposit recyclable items separately based on the type of material (“source-separated recycling”), as opposed to the commingled blue bins, where all recyclables, regardless of type, are disposed of in one bin.