Plastics are polymers (from Greek poly for many and mer for a unit or part), which are thus made up of many identical repeating units – hundreds or thousands of them – like beads making up a necklace or a rosary. Each unit is called a monomer. For example, ethylene is a monomer and many units of ethylene, when joined, form a polymer, namely polyethylene. 

The monomers themselves are typically made of carbon and hydrogen (and sometimes oxygen), collectively referred to as hydrocarbons, which can be sourced from plants or from crude oil, natural gas, or coal (fossil fuels).

Plastics are mostly made from hydrocarbons extracted from crude oil in four steps.

1. Extraction. Crude oil is extracted from oil wells.
2. Refining. Crude oil is separated, by heating, into different products, each emerging at a different temperature.
   
3. Polymerization. The monomers obtained from refining process are combined into polymers. 
4. Compounding and processing. The liquid polymers turn solid at room temperature and are moulded into pellets. Different chemicals are added to the pellets to obtain desired properties in products.  

Most of the plastics we use today, as products or packaging material, are made from hydrocarbons extracted from crude oil and natural gas. The process consists of the following steps.

1. Extraction. Crude oil or natural gas is extracted by drilling wells or from gas reservoirs and sent to oil refineries.
2. Refining. In a refinery, crude oil, which is a mix of thousands of compounds, is separated into different products by heating: kerosene, gasoline, naphtha, light oil, and heavy oil are just some of these products, each emerging at a different temperature. Naphtha is the source of most of the monomer units used to make polymers. 
3. Polymerization. The monomers (such as ethylene and propylene) thus obtained are combined, using high temperatures and some catalysts, to form polymers (such as polyethylene and polypropylene).
4. Compounding and processing. As the polymers – initially liquids – begin to form, they turn into solids at room temperature and can be moulded into pellets. These pellets are transported to plastic-making factories. Chemical additives, fillers, dyes and pigments are added to the pellets as required to obtain plastic products with desired properties. These chemicals can affect the recyclability of the plastic product.

Plastics can be grouped into two major families.

Thermoplastics soften when heated but harden again on cooling, which makes them suited to recycling. Thermoplastics are used in packaging and consumer goods.

Thermosets retain their shape once moulded, do not soften when melted, and therefore cannot be recycled. Thermosets are used in electrical appliances and as construction materials.

Plastics can be grouped into two major families.

• polyethylene (PE; can be high-density polyethylene or low-density polyethylene): shampoo or hair oil bottles, oil containers, carry bags
• polyethylene terephthalate (PET): soft drink bottles, water bottles
• polyvinyl chloride (PVC): pipes, window frames, slippers/sandals
• polypropylene (PP): caps for bottles, takeaway food containers
• polystyrene (PS): thermocol, single-use plates
• expanded polystyrene (EPS): packaging for electronic goods, insulation in buildings

Thermosets, unlike thermoplastics, cannot change their shape once moulded and do not soften or melt when heated and therefore cannot be recycled. Thermosets are extensively used in electrical appliances and as construction and aerospace materials. Some examples of thermosets and their common uses include the following.

• epoxide (EP): circuit boards, paints, adhesives
• phenol-formaldehyde (PF): plywood, electrical components, automotive parts, wood adhesives
• polyurethane (PUR): shoe soles, adhesives, tires, paints, mattresses, cushions
• unsaturated polyester resins (UP): automotive parts, construction materials, paints.

One of the more common ways to classify plastics, one that many of us find easier to relate to, is to use numbered categories—the numbers 1 to 7 commonly seen on everyday plastic products and packaging (Table 1). These numbers are known as the resin identification code (RIC), which classifies plastics based on the type of polymers they are made from. These numbers could help waste collectors and recyclers in identifying plastics based on their polymer types. However, whether a plastic item is ultimately recycled depends on several other factors as well. Simply having the identification code does not mean that the packaging or product will be recycled.

Table 1 Categories of plastic and examples of use

Single-use plastics are designed to be used only once and thrown away after that. All disposable products fall into the category of single-use, which include plastic spoons, cups, plates, stirrers, and so on. 

Such items are often used on the go and are therefore often found as litter in cities, villages, and beaches.

This is a list of items of single use, but a large proportion of plastic packaging also falls into single-use category. Some countries and organizations around the world and in India use the term ‘unnecessary’ or ‘problematic’ to refer to such plastics.

The industry typically associated with such plastics is the industry built around FMCG, short for fast-moving consumer goods. The India Plastics Pact, an initiative of the Confederation of Indian Industry, works with FMCG businesses and other stakeholders along the plastics value chain to create a circular economy for plastics packaging. Signatories to the Pact have come up with a list, called the Ambition List, that identifies ‘unnecessary’ or ‘problematic’ plastics, going beyond the central government’s list of banned items mentioned earlier. The Ambition List includes the following items.

• Bottles, PVC pallet wraps, PVC shrink sleeves, and labels made of PVC
• All polystyrene packaging (including EPS)
• Oxo-degradable plastic packaging
• PET-G labels or sleeves on PET bottles
• Biodegradable polymer packaging not compliant with the Indian Standard 17899 T:2022: Assessment of biodegradability of plastics in varied conditions
• Plastic packaging not detectable in automated sorting systems using near-infrared detection.

Citizens have an important part to play in reducing waste from single-use items by choosing reusable and durable products whenever possible.

To address the challenge of plastic pollution, alternatives such as bioplastics, biodegradable plastics, and compostable plastics have emerged in recent years. However, citizens are often confused about such plastics because although the terms ‘bio’ and ‘compostable’, which suggest that the plastics are ‘green’ and ‘environment-friendly’, the materials can have the same look and feel as conventional plastics. Read more to know some important differences between such plastics and conventional plastics.

To address the challenge of plastic pollution, alternatives such as bioplastics, biodegradable plastics, and compostable plastics have emerged in recent years. However, citizens are often confused about such plastics because although the terms ‘bio’ and ‘compostable’, which suggest that the plastics are ‘green’ and ‘environment-friendly’, the materials can have the same look and feel as conventional plastics making it hard to distinguish between the two — which is why we describe here some important differences between such plastics and conventional plastics.

Bioplastics

Bioplastics is an umbrella term and can mean

1. plastics that are bio-based (in that the hydrocarbons from which the polymers are made are derived from plants or biomass) or
2. plastics that are biodegradable (can be completely broken down by microbes in a reasonable time frame under specific conditions), or
3. both¹.

However, not all bioplastics are biodegradable, and not all bioplastics are bio-based (Figure 1).

Figure 1. Types of plastics (Source The UK Plastics Pact, 2020)

Bio-based plastics

Bio-based plastics are plastics that are made of plant-based raw material or feedstock (unlike conventional plastics, which are made from fossil-fuel-based materials or feedstocks). Typical plant-based materials are maize starch, cane sugar and vegetable oils. Bio-based plastics are often made of polylactic acid (PLA), which has properties similar to those of conventional plastics, making them and bio-based plastics similar in terms of look and feel.

Bio-based plastics can be made fully or partly from plant-based feedstock,² which means that they can be either biodegradable or non-biodegradable.

Biodegradable plastics

Biodegradable plastics are plastics made of materials that can be – under specific conditions – degraded or decomposed at the end of their useful life by the action of living organisms, usually microbes, into water, carbon dioxide, and biomass.

Again, biodegradable plastics can be either bio-based or fossil-fuel-based, depending upon the feedstock or raw materials used in producing them.

Compostable plastics

Compostable plastics are a subset of biodegradable plastics and are designed to break down into water, carbon dioxide, and biomass—but only under specific conditions and within a definite time frame.

Compostable plastics can be degraded - but only under specific conditions and over a definite time frame. Several conditions must be satisfied before using compostable plastics or switching to them from conventional plastics.

1. Compostable plastics must be collected separately from conventional plastics.
2. The infrastructure required for processing compostable plastics must be available.
3. The end product should have a strong market.
4. Compostable plastics must be prevented from contaminating the normal recycling stream. 

While compostable plastics are an attractive proposition, it is good to know that they degrade only under specific conditions and over a definite time frame. The following points, therefore, need to be considered before using compostable plastics or switching to them from conventional plastics.

Compostable plastics must be collected separately from conventional plastics. At the household or consumer level, bags bearing the label or stamp ‘compostable’ must be collected separately and sent to industrial composting facilities. If such bags are not kept separate, will get mixed with conventional plastics, hampering the recycling of conventional plastics.

The infrastructure required for processing compostable plastics must be available. Appropriate industrial composting facilities should be set up to handle compostable plastics at the scale required.

The end product should have a strong market. If compostable plastics are to be a viable alternative to conventional plastics, the product made after industrial composting should have a strong market.

At present, very small quantities of compostable plastics are placed on the market, making it uneconomical for waste workers to collect. Since, they are not clearly labelled, it is hard for waste workers to identify and segregate (separate) them out. Even if compostable plastics are collected and processed, there is, at present, limited demand for the end product (compost). As a result, compostable plastics are less preferred compared to conventional plastics.

Compostable plastics must be prevented from contaminating the normal recycling stream. In the absence of universal labelling, compostable plastics are indistinguishable from other kinds of plastics. A lack of clear labelling may result in compostable plastics getting mixed with conventional plastics, thereby contaminating the stream of recyclable plastics and lowering the quality of recycled plastics obtained from that stream. (Compostable plastics are not compatible with machinery used for recycling conventional plastics.)

Compostable plastics should be considered as alternatives to conventional plastics only if they 

1. are certified as compostable to an international compostability standard (for instance, EN14342 or any equivalent Indian standards),
2. leave no microplastic residue,
3. are clearly labelled as compostable, and
4. are used and disposed of in closed-loop or controlled systems with appropriate infrastructure available for effective treatment (hotels, malls, catering services, and airports, for example, are places that can meet these conditions).

Compostable plastics should be considered as alternatives to conventional plastics only if they 

1. are certified as compostable to an international compostability standard (for instance, EN14342 or any equivalent Indian standards),
2. leave no microplastic residue,
3. are clearly labelled as compostable, and
4. are used and disposed of in closed-loop or controlled systems with appropriate infrastructure available for effective treatment (hotels, malls, catering services, and airports, for example, are places that can meet these conditions).

Plastic recycling typically involves the following steps.

1. Collection from households, businesses, and public spaces
2. Sorting by polymer type, colour, and quality (manually or mechanically)
3. Cleaning to remove contaminants
4. Shredding into flakes
5. Melting into pellets
6. Making into new products 

Plastic is a popular and versatile material with several applications, and recycling plastic offers several benefits.

Recycling

• reduces the need for extracting, refining, and processing precious raw materials
• saves the energy used for producing virgin (fresh) plastic materials
• saves water (production of virgin, or new, plastics requires more water than that for recycling plastics)
• decreases the amount of waste going to landfills
• lowers emissions of gases into the atmosphere
• generates employment opportunities. 

A wide range of products can be made from recycled plastics including

• packaging materials such as bottles, food trays, containers, carry bags, and wrapping film
• consumer goods such as furniture, textiles, electronics, clothing, and automobile parts
• construction materials such as plastic pipes, tiles, roofs, walls, and insulating materials.

The best case is when recycled plastics are used to make the same product again (closed-loop recycling). 

A wide range of products can be made from recycled plastics including

• packaging materials such as bottles, food trays, containers, carry bags, and wrapping film
• consumer goods such as furniture, textiles, electronics, clothing, and automobile parts
• construction materials such as plastic pipes, tiles, roofs, walls, and insulating materials.

The best case is when recycled plastics are used to make the same product again (closed-loop recycling).

Although recycling offers significant environmental, social, and economic benefits, it is important to remember the following points.

• Recycling is an energy-intensive process that requires infrastructure and investment.
• Not all plastics are recyclable; more important, most plastics can only be recycled 7 to 9 times.
• Contamination reduces the quality and value of recycled plastics. At present, segregating different kinds of plastics at source remains fairly low in India, which lowers the quality of recycled material.

For any material (paper, plastic, glass, etc.), its waste-management hierarchy (Figure 2) is the most preferred option, whereas disposal is the least preferred option. Recycling, therefore, must be preferred only when it is not possible either to prevent the use of a given material in the first place or to reuse it.

Figure 2. Hierarchy of waste management

The waste that we generate at home, also known as municipal solid waste (MSW), is a mix of materials, including biodegradable waste, non-biodegradable waste, and hazardous waste.

Segregation at source refers to segregating waste at the point at which it is generated – homes, offices, parks, and malls, for example – into two separate streams: wet and dry. Waste can be segregated into many other categories too; for example, in some countries paper, metal, glass, and plastic waste is each collected separately at the household level.

Wet waste is mainly kitchen and garden waste and includes vegetable and fruit peels, leftover food, etc. and can be composted. Dry waste comprises plastic, paper, glass, and metal, all of which are recyclable. 

Segregation of waste at source is the first step in effective waste management and is useful in many ways.

Segregation

• facilitates composting of wet waste, which is about 50% of the total waste we generate daily (The compost made from wet waste is rich in nutrients, which can be added back to the soil to enhance its quality.)
• prevents contamination of dry waste, resulting in better recycling and the recovery of valuable resources
• lowers the costs of segregating waste later by waste workers and of removing contaminants from recyclable waste streams
• decreases the amount of waste sent to landfills, thereby reducing the contamination of soil and water from leachate: a toxic liquid formed when rainwater and moisture present in waste mix with hazardous and unsegregated waste in landfills.

Used packaging and plastic products or discarded objects are collected, segregated, and sent for recycling. The recycled materials are made into new products or used for remaking the same product.

Some plastics are burned to produce electricity. Although this option reduces the volume of plastic waste, it pollutes the environment.

If not managed properly, plastics end up in landfills, where they remain intact for hundreds of years.  If streets, parks, and beaches, for instance, are littered with plastics, they can eventually reach the ocean, harming marine life and natural ecosystems.

Proper management of waste is thus crucial in deciding the ultimate fate of plastics.

Used packaging (containers, bottles, etc.) and plastic products or objects thrown away as municipal waste are collected by waste workers and separated into different streams depending on the resin of which they are made. The collected and separated materials are then sent to recycling facilities for washing, shredding, and processing. The pellets resulting from the process can be made into new products or used for making the same product (bottles, for example) yet again.

Some plastics are also burned in waste-to-energy plants to produce electricity. Although this method can reduce the volume of plastic waste, the burning can release pollutants if emissions are not properly controlled; of course, all burning releases greenhouse gases into the environment.

However, if not managed properly, plastics can end up in landfills, where they can persist for hundreds of years.  If streets, beaches, and parks, for instance, are littered with plastics, they can eventually reach the ocean, harming marine life and natural ecosystems.

Proper management of waste at the consumer level through segregating waste at source and ensuring that plastics are not littered is thus crucial in deciding the ultimate fate of plastics.

Reducing means using less. Reducing plastic consumption can have several benefits.

• Plastics are made from fossil fuels, and reducing our use of plastics reduces the need for extracting these finite resources.
• Reducing generates less waste, which means smaller volumes to be recycled and for landfills.
• Consuming less saves energy and water used in producing and recycling plastics.
• Using less of plastics means lowering the emissions of greenhouse gases. 

Reducing means using less of something; however, modern living and changing lifestyles, production, and overconsumption are widespread.

Reducing our consumption of plastics is beneficial in many ways.

• Plastics are made from fossil fuels (oil and gas) and reducing our use of plastics reduces the need for extracting these finite resources. Single-use plastics are especially problematic because we discard them after using them only once.
• Reducing generates less waste, which means smaller volumes of waste have to be recycled and ultimately sent to landfills.
• Consuming less saves the amount of energy and water used in producing and recycling plastics.
• Using less of plastics means lowering the emissions of carbon dioxide and other greenhouse gases that are emitted at all stages of manufacturing plastics from production to improper disposal.

We can reduce our consumption of plastics in many ways.

• Simply using less: for example, carrying a bag when we go shopping.
• Reusing: technically, reusing is a part of reducing. Reusing is using things again and again and getting the most out of them. Thus, instead of buying a single-use plastic bottle, it is better to use a steel or glass bottle, which is reusable.

We can reduce our consumption of plastics in many ways.

• Simply using less: for example, carrying a bag when we go shopping or cooking food at home more often, thereby cutting down on ordering food online (and thereby reducing packaging materials)
• Reusing: technically, reusing is a part of reducing. Reusing is all about using things again and again and getting the most out of them. Thus, instead of buying a single-use plastic bottle, it is better to use a steel or glass bottle, which is reusable.

By reusing things, we reduce the amount of new or virgin plastics required to make multiple single-use items. 

The India Plastics Pact unites stakeholders across the plastics value chain to reduce plastic waste and seeks to eliminate, by 2030, all unnecessary or problematic plastics; solve the problem through redesign and innovation; and make all plastic packaging reusable, recyclable, or compostable.

Brands and businesses can reduce the use of plastics in many ways.

• Complete elimination of unnecessary and problematic plastic items 
• Elimination by switching to alternative packaging materials
• Reduction in per unit weight of packaging
• Reduction through overall decrease in using plastic packaging

Signatories to the India Plastics Pact are committed to reducing their plastic packaging. Read our Annual Report 2022/23 to know more. 

A great deal of work is under way in India through such initiatives as the India Plastics Pact, which unites stakeholders across the plastics value chain – including brands, retailers, packaging producers (converters), waste management organizations, NGOs, and more – to reduce plastic waste.

The India Plastics Pact has set itself a target to eliminate, by 2030, all unnecessary or problematic plastic packaging and items and instead address the problem through redesign and innovation. Within the same time frame, the Pact aims to make all plastic packaging reusable, recyclable, or compostable.

 In the context of brands and businesses, reduction can be done in many ways.

• Complete elimination of plastic items that have been identified as unnecessary and problematic plastic items: by eliminating them, ultimately we prevent such plastics from being manufactured in the first place 
• Elimination by switching to alternative packaging materials such as paper, glass, and metal
• Reduction in per unit weight of plastic packaging
• Reduction through an overall decrease in the use of plastic packaging

Signatories to the India Plastics Pact have taken proactive actions to reduce their plastic packaging. Read our Annual Report 2022/23 to know more.

As citizens, we all have a part to play in reducing plastic pollution. Although recycling is a key part of this, it is important to remember that, whenever possible, we should focus on reducing (and reusing) before recycling.