material is any of a wide range of synthetic or semi-synthetic organic solids that are moldable. Plastics are typically organic polymers of high molecular mass, but they often contain other substances. They are usually synthetic, most commonly derived from petrochemicals, but many are partially natural.

Most difficult to decompose under natural plastics, incineration will bring air pollution problems, so bags made ​​of plastic so is therefore era magazine's "50 worst inventions", plastic bags are also on the list this is because the human consequences of selfish arbitrarily discarded plastic bags. In particular, plastic bags are widely used, so environmental organizations have focused on plastic bags. Reduce the use of plastic bags is currently one of the methods to reduce the environmental impact of plastic bags, such as Hong Kong has no plastic bag day environmental groups held regularly since 2006 to encourage the public to reduce the use and more on July 7, 2009 in the collection of plastic solid bag levy to reduce the use of plastic bags; has begun to collect plastic bag tax countries in order to achieve a decrease of the use of plastic bags. Another plastic bag also started to be considered environmentally friendly [1] bags instead of other materials, such as paper bags, reusable shopping bags, and biodegradable plastics to manufacture plastic bags and so on. But these high material costs compared to plastic bags, so most places are still the main use of plastic bags.