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KOCHI: With the state government imposing ban on single-use plastic, biodegradable plastic has acquired immediate relevance. Many shopping malls have started replacing single-use plastic with ‘biodegradable’ plastic.

A biodegradable material, which is less hazardous to wildlife and environment, would degrade to little or nothing over a period of time. “The biodegradable plastic will degrade. But depending on the material used, it may take a minimum of two years to even 20 to 30 years to degrade,” said K Sreekumar, professor at department of applied chemistry, Cusat.

Though the state government recently introduced guidelines for compostable materials, it is inadequate and strict implementation remains a problem. The compostable plastic product needs to be approved by Central Pollution Control Board (CPCB) and should dissolve in dichloromethane (methylene dichloride).

“Licence is given to only those biodegradable bags that can be composted in 180 days. But we have restricted the usage of biodegradable bags. It is not allowed as carry bags, cutlery. We are only allowing it as garbage bag cans. Right now, it may also be used as a replacement for plastic packets that are not banned,” said Suchitwa Mission executive director Mir Mohammed Ali.

In a recent study at the University of Plymouth, UK, compostable, biodegradable, oxo-biodegradable and conventional polythene plastic bags were tested in three different natural environments — buried in the ground, outdoors (exposed to air and sunlight), and submerged in the sea. It showed that none of the bags broke down completely in any of the environments tested. In particular, the biodegradable bag survived in soil and sea almost unscathed.

The researchers further said that some biodegradable plastic may be ‘compostable’, but evidence suggests that they do not biodegrade completely but instead break down into microplastics which may persist in the environment. As a result, the European Union is taking steps to restrict the use of these plastics.

No wonder the state government is also adopting a wait and watch policy when it comes to biodegradable plastic. “This is a dynamic ban and based on usage and inspections, we will be revising it,” said a senior government official.

