In many countries, you can find the universally recognized recycling symbol – three chasing arrows – on plastic products. But not every plastic item with this symbol can be easily recycled. In fact, although plastic recycling technology has been around for decades, most of our plastic waste today still ends up in landfills.

While millions of tonnes of our plastic waste pile up in landfills and in the natural environment, many people are wondering why recycling rates are so low.

We’ve gathered some of the most common questions to explain the recycling process – and its limitations – and help you navigate this complex topic.

How much plastic is recycled today?

Recycling rates vary by location, plastic-type and application. Scientists estimate that only around 9 per cent of all the plastic waste generated globally is recycled. Most of our plastic waste – a whopping 79 per cent – ends up in landfills or in nature. Some 12 percent is incinerated.

Why are we not recycling more plastics?

In principle, most plastic materials could be recycled. However, in practice, recycling faces many barriers:

• Contamination: Plastic waste is often contaminated with labels, food remains or other materials. For example, putting products in the recycling bin that can’t be recycled can contaminate the waste stream and even damage recycling equipment. This lowers the quality of the recycled product and can complicate the sorting process. If the waste stream is too contaminated, it cannot be recycled at all, and everything is diverted to a landfill.

• Harmful chemicals: Plastics contain a complex blend of chemical additives to lend them specific properties such as flexibility, color or water repellence. Many of these substances are harmful to human health. Recycling plastic products containing hazardous chemicals can result in long-term negative health impacts for workers, local communities and end-product users.

• Profitability: There are thousands of different types of plastic, each with unique properties that affect their structure, colour and melting point. As these materials cannot be processed together, collection, sorting and treatment are much more complicated and expensive. For example, one of the most common plastics, polyethylene terephthalate (PET), is said to be 100 percent recyclable. But green PET bottles cannot be recycled with clear PET bottles.

How often can plastic be recycled?

Each time plastic is recycled, the quality of the material degrades. As different materials are being mixed in the recycling process, harmful chemicals can accumulate. Therefore, most plastics are only recycled once or twice before being disposed of in landfills or incinerators. Much of today’s recycling is merely postponing final disposal, not preventing waste.

What do the numbers on plastic products mean?
Many plastic products display a small number between one and seven inside a chasing arrows symbol. This is called a resin identification code. It was introduced by the plastic industry in the 1980s and identifies the type of plastic used. It is not an indication that a product is recyclable.

Resin Code #1: PET (Polyethylene Terephthalate) – products like beverage bottles or food containers
Resin Code #2: HDPE (High-Density Polyethylene) – products like milk jugs or detergent bottles
Resin Code #3: PVC (Polyvinyl Chloride) – products like pipes or cable insulation
Resin Code #4: LDPE (Low-Density Polyethylene) – products like plastic bags or wraps
Resin Code #5: PP (Polypropylene) – products like yogurt tubs or medicine bottles
Resin Code #6: PS (Polystyrene) – products like disposable plates or cups
Resin Code #7: All other Plastics – anything that doesn’t fit under the previous categories

Which types of plastics are recycled most?

The most recycled plastic items are Resin Code #1 and #2. Plastic products with resin codes #3 to #7 are more challenging and therefore often not financially viable to recycle. Anything from coffee cup lids to takeout containers and yoghurt tubs are rarely recycled.

How is plastic recycled?

While recycling processes may vary depending on location, equipment and other factors, generally they follow these steps:

• Collection: consumers deposit plastic into a recycling container;
  Sorting: facilities sort plastic from other materials and by different plastic type;
• Cleaning: the material is washed and dried to remove contamination;
• Reprocessing: plastic is ground into flakes, heated and pressed into new pellets;
• Production: the pellets are melted and formed into new plastic products.

What is the difference between recycling and downcycling?

Recycling means processing used plastic materials into new products. For example, recycling PET bottles into recycled PET pellets.

Downcycling means transforming plastics into products of lower quality compared to the original material. This happens due to changes in the molecular structure during the recycling process that result in products less suitable for high-performance applications. For example, turning a PET bottle into lower-quality polyester fiber for clothing. Most processes described as recycling today are actually downcycling.

Plastic waste needs to be collected, sorted, cleaned and reprocessed into pellets before it can be melted and formed into new usable products.

What can we do?

Relying on recycling won’t solve the plastic crisis. But there are numerous measures along the plastic lifecycle that can help tackle the plastic crisis and protect people’s health in the process, including:

reduce the use of inessential plastics;
stop the production and consumption of inessential single-use plastics;
champion the transition to zero-waste communities;
establish transparency and traceability of chemicals used in plastics;
detoxify plastic products: phase down and eliminate the use of hazardous chemicals in plastics;
stop the recycling of plastics containing hazardous chemicals;
simplify and harmonize plastic materials;
enforce extended producer responsibility.

How can you help?

In addition to taking daily actions to reduce your own plastic footprint, you can:

hold your government representatives accountable, and advocate for an ambitious global plastic treaty;
advocate for and support the implementation of policy and legislation to reduce plastic production, boost circular models, improve waste management and hold polluters accountable;
support initiatives that reduce plastic pollution, and advocate for businesses to act;
become an advocate for reducing plastic pollution yourself, and help change others’ behaviours.
In addition to reducing personal use of plastics, individual actions can include advocating for greener governmental policies and supporting initiatives that reduce plastic pollution.

What next?

At the fifth UN Environment Assembly, 175 nations agreed to begin negotiations on a legally binding treaty on plastic pollution that addresses the full lifecycle of plastic.

This historic agreement could help create the necessary accountability and transparency to transform the way we produce, consume and dispose of plastics.

The negotiations are currently at the mid-point.

This blog was originally published by UNDP.