Maharashtra has become the latest state in India to ban plastic bags of a certain thickness. But what’s wrong with plastic bags? Why do so many people claim that they are dangerous to man, the environment and other living things?

The first problem with plastic bags stems from the sheer number produced and used. Environmental groups estimate that up to 1 trillion bags are now used worldwide every year. The other problem is the material the bags are made out of -- plastic.

Plastic is made from petrochemicals, the name given to products created when naturally occurring oil is treated in various ways; the most common petrochemicals are types of petrol and diesel.

The main reason petrochemical products are useful is that they can form various types of long chains of hydrogen and carbon molecules. Some of these chains, called polymers, react in different ways to heat and pressure. Plastic is the name given to a wide variety of petrochemical polymers that are solid in ordinary temperatures but can be heated to form shapes, or moulded. Such material, especially one called polyethylene, can be flattened into sheets and then shaped into bags.

Since they were first introduced in the 1950s in the United States, plastic bags are now everywhere. They are light and waterproof. And making them is so cheap that even the smallest shopkeeper can afford to give them away with the tiniest of purchases. The usefulness of plastic bags cannot be questioned -- they protect and store food and other products; they enable us to carry things around; and they allow us to easily dispose of our garbage.

Yet, as with other things made out of petrochemicals, plastic bags increase our dependence on oil. Because of global warming, as well as the water and air pollution created while transporting and pumping it, most people who care about the environment are against the use of oil. Another worry is our reliance on imported oil. We become too dependent on other countries; wars are being fought over oil. Since we cannot do without oil totally, people say we should at least cut down on our use of it, and this includes petrochemical products like plastic.

A major problem with plastic products is: what to do with them once we’ve finished with them. A common quality of most petrochemicals is that they burn very easily, which is, of course, why we use them as sources of power. So the tendency is to burn waste plastic. Unfortunately, when burned, plastics give off extremely dangerous poisonous gases. This is especially true with plastics that have other things added to them to give them a specific consistency, strength or colour. The most dangerous gas given off is one called ‘dioxins’, which is created if there is chlorine or chlorine compounds in the plastic (or even in the incinerator where the plastic is being burned!). In small quantities the illnesses caused by such gases may not be obvious, but in large cities where waste is regularly burned, people’s health suffers. Though the danger of dioxins is well-known, in countries like India we will only know the effects years from now as there is very little monitoring of pollution-related health problems in our country, and also because it’s the poor who suffer first.

So what do you do with used, waste plastic? Where city waste is not burned, it is usually put into large dumps called ‘landfills’. In landfills, most things slowly break down, ‘degrade’ and return to nature. This happens just by the effect of time and chemical action, like, for example, when things rust. Other things degrade by the action of living things like bacteria or fungi. Unfortunately plastic does not degrade very well: a piece of plastic may take up to 1,000 years or more before it falls apart! So it will just sit and sit in a landfill. And soon more and more landfill space will be required. Remember, because of all the unhealthy waste products that are stored in landfills, these areas cannot be used for anything else. And so, valuable land has to be kept aside only for this purpose, for years.

Many things can be recycled to reduce waste. Recycling means breaking down a manufactured product into its basic constituents, the material that it is made up of, and then turning that material into new products. For example, glass bottles or steel furniture can be melted and refashioned into other things once we have finished with them. But most commonly used forms of plastics do not recycle very well. Each time a piece of plastic is melted down for reuse its quality worsens and it can only be used in a low-quality product. And anyway, since new plastic is very cheap, recycling of plastic is not given much importance. This means that plastic waste products just keep on increasing.

Thin plastic bags are considered a bigger menace because they are more difficult to recycle, as their lightness means that you need a lot more of them to get a reusable amount of plastic. In India, since rag-pickers and paper merchants are usually paid by weight for the amount of garbage they collect, it is not worth their while to spend much time collecting thin bags when they could instead be looking for heavier stuff. So, very few plastic bags are collected, adding to the trash disposal problems. Also remember, because they are so light and tear easily plastic bags cannot be reused, so people usually throw them away after one use. Thicker bags can at least be used a few times.

Thin plastic bags pose a serious hazard to the environment as they get so easily blown around. In cites in India, stray cattle and dogs eat them as they smell the food that was once stored in them. The animals that eat these bags quickly get sick and die. Wild animals get trapped in them and suffocate. This is especially true for marine animals like turtles and seals. Thousands of large marine animals die every year because of plastic bags.

Plastic bags also block and choke streams and rivers. Last year’s floods in Mumbai were partly due to sewers and drainage areas becoming blocked with trash, a large part of it plastic bags. The flooding killed people, stopped businesses and cost the city millions of rupees. Which is why the state government banned the use of thin plastic bags. Bangladesh too has banned plastic for the same reasons. Other countries have a tax on bags so that no one gives them away free, and people think twice before using them.

You can help reduce the number of plastic bags. When you buy things:

• Do without a bag, if it’s easy to carry the things you buy. 
• Use cloth or strong paper bags and take your own bags with you when you go shopping.
• Say no when the shopkeeper automatically puts your purchases into a plastic bag.

-- Manoj Nadkarni

InfoChange News & Features, March 2006