ACCORDING TO REPORTS, South China's Hainan province is aiming to introduce the first local standards for full biodegradable plastic and will totally ban the production, sales, and use of one-off, nondecomposable plastic bags and tableware. Beijing News comments:

Before the end of 2025, the province aims to completely ban the production, sales and use of plastic products listed in the Hainan Province Prohibition on the Production, Use and Disposal of Non-Degradable Plastic Products. Many people have asked what can be used to replace the non-decomposable plastic bags and tableware once they are banned. One answer is to use bags and tableware made of decomposable plastics.

That sounds a good idea. But is it practical?

Currently, by saying "decomposable plastics", we mainly refer to those that can be decomposed by bacteria and other microbes, and the most common of them is Polyactic acid (PA).

PA is made from plants and it can be produced in large quantities at quite low cost, which make it a good candidate for decomposable plastic materials. However, it can decompose only under very strict conditions: The dampness must be between 50 and 60 percent, while the temperature must be between 50 C and 70 C. Even under these conditions, it takes months for it to decompose.

It is very difficult for natural temperature to reach 50 C. In other words, you cannot dispose a PA plastic bag at will. The United Nations clearly pointed that out in a 2015 report.

Especially, quite a high percentage of discarded plastic bags end their journey in the ocean, where it is rather difficult for PA to decompose. In an experiment, PA plastics stayed almost unchanged for 300 days in salty and fresh water.

Besides PA, other "decomposable" plastic materials have very strict conditions for decomposing. If the conditions are not met, the degradable plastic is basically the same as ordinary plastics, and it will become plastic garbage, which becomes micro-plastic, polluting the ocean and water.

Even if Hainan's move forces the development and improvement of biodegradable plastics technology, the fundamental solution is still to reduce the consumption of disposable plastic products. Only when people give up the habit of using plastic bags to wrap up each of the items they buy will the total amount of plastic bags drop.