As global concern over plastic pollution rises, corporate giants such as Coca-Cola and Unilever are pumping cash into a recycling initiative in Kenya they hope will provide a model for other developing countries.

However, the voluntary scheme lacks legal backing, leaving a few companies to pick up the bill for everyone — a problem that doomed a similar program here before.

Many multinationals are scrambling to support recycling, stung by criticism from environmentalists over pollution and keen to be able to re-use valuable polyethylene terephthalate (PET) plastic. Single-use plastic is a key topic at next week's global United Nations Environmental Program summit.