South Australia was the first Australian state to ban lightweight plastic supermarket bags, phasing in the new laws from 1 January to 4 May, 2009. The ban aimed to reduce the more than four billion plastic checkout bags Australians used each year. The Northern Territory and the Australian Capital Territory introduced similar bans in 2011. At the time of the South Australian ban, China, Bhutan, Bangladesh and Rwanda had already banned light weight plastic bags.
Lightweight plastic supermarket bags may be convenient, but are a major environmental problem. Some estimates suggest that 100 million marine animals die each year directly from the consumption of plastic waste. The bags cause litter problems, clog storm drains and, even when they make it into landfill, will take around 400 years to degrade.
Increasing consciousness of the danger plastic supermarket bags form to marine and other wildlife, and the cost of cleaning up plastic litter, prompted the South Australian government to pass legislation to ban them. Other jurisdictions followed, and public pressure led leading retailers Coles and Woolworths to stop supplying single-use plastic bags in mid-2018.