Three stalls selling picnic plates made of sal leaves have come up inside Alipore zoo to provide visitors an alternative to thermocol, a material less vilified than plastic but just as harmful to the environment.

The green initiative also serves a social cause. The sal leaves come from a forest in West Midnapore, giving a section of villagers there an additional source of income.

Till sal plates were made available inside the zoo, visitors carrying lunch or snacks would mostly use thermocol to serve food. “The change started on January 1. We have put up several banners and posters, asking visitors to abandon thermocol plates. We have deployed personnel at the gates to check bags. Penalties will be introduced later,” zoo director Asis Kr Samanta said.

Thermocol, a non-biodegradable material, is a brand of the German company BASF and an expanded form of polystyrene. The end point for most thermocol are landfills or the sea. Thermocol takes hundreds of years to decompose. When burned, it releases hazardous chemicals and toxic gases.