At the Indonesian city of Surabaya, passengers can exchange bags full of plastic bottles and disposable cups for bus tickets. The nation is the world’s second largest marine polluter, behind China, and has pledged to reduce about 70 percent of its plastic waste in its waters by 2025.

The Surabaya scheme has proven popular in the city of 2.9 million, with 16 000 passengers trading trash for free bus travel every week. An hour-long bus ride with unlimited stops costs three large bottles, five medium bottles or 10 plastic cups. However, the recyclables must be cleaned and cannot be squashed.

Franki Yuanus, a Surabayan transport official said in a statement that the programme aims not only to reduce waste but also to improve traffic congestion by encouraging people to switch to public transport. He added that the programme has received favourable response from the public. He said that “paying with plastic is one of the things that have made people enthusiastic because up until now, plastic waste was seen as useless.” Authorities said that roughly six tonnes of plastic rubbish are collected from passengers each month before being auctioned off to recycling companies.