China is set to join a growing number of countries cracking down on single-use plastic items, with multiple bans expected to come into force gradually over the next six years.

The new policy, announced Sunday, is slated first to take effect in major cities, where many of the non-biodegradable plastics found in the world’s oceans originate. Microplastics threaten the health of fish and other marine animals, through which the harmful materials enter the human food chain.

In large Chinese cities, the distribution of plastic bags is set to cease by the end of the year, whereas smaller cities and rural areas have until 2022. Some exceptions will allow the use of reusable, thicker bags or other plastic bags through 2025.

Among other items set to be phased out over the next few years are many utensils distributed by food delivery companies and restaurants, including single-use straws.

The Chinese effort, if fully implemented, could be among the most significant developments so far in what analysts and advocacy groups describe as a global “war on plastic.” Between 1950 and 2015, the global production of polymer resin and fiber — generally referred to as plastic — rose from 2 million to 381 million metric tons annually. Most recently, new economic superpowers, including China, have accounted for the largest year-on-year increases, even though Western countries are still responsible for some of the highest per capita production rates.

This glut has seen an attendant rise is policies meant to reduce reliance on plastics. Here are some of the places where drastic steps have been taken.

Rwanda: The central African country was an early front-runner in what has become a movement. Under President Paul Kagame — often hailed by supporters as a hero for his role in Rwanda’s recently flourishing economy but also criticized as an authoritarian who has cracked down on free expression — the country adopted one of the world’s toughest stances on the issue more than a decade ago.

Between 2006 and 2008, his government made the import, sale and use of non-biodegradable plastic bags and most packaging illegal and punishable with prison sentences of up to one year, fines or forced public apologies. The country’s school curriculums were changed to include lessons on the subject.

Officials said rivers had been clogged with plastic waste, which worsened floods. Such waste can also prevent rain from entering the soil, exacerbating droughts, or pose lethal risks to wildlife.

But Rwanda’s success in combating plastic pollution has come at a cost, critics of Kagame say, pointing at what some view as excessively harsh punishments.

Rwanda has nonetheless become a model for similar efforts across Africa. Kenya and Tanzania are among the countries that have followed suit.

Pakistan: Last August, the Pakistani government banned all single-use polyethylene bags in the country’s capital region, home to some 1.5 million people.

Authorities vowed to enforce the ban on the manufacturing, sale and use of the bags with steep fines. Manufacturing plastic bags carries the harshest penalty, at the equivalent of $31,000. The use of a single bag can be punished with a $31 fine, according to The Washington Post’s Pamela Constable.

While environmental protection groups celebrated the move, industry representatives warned it would come at a huge financial cost: Banning the production of plastic bags, they cautioned, could result in the unemployment of half a million people in a nation already strained by a deteriorating economy.

“They should first find new jobs for the plastic factory workers and then ban the bags,” 38-year-old fruit seller Nazeer Abbasi told The Post last year, when the ban took effect in the Islamabad region.

Additional bans have since been implemented outside the capital. But Pakistani government officials acknowledged to the Nikkei Asian Review that full enforcement of the rules could be delayed by several years.

India: Similar challenges may stand in the way of the implementation of a nationwide ban on single-use plastics in India. In 2018, Prime Minister Narendra Modi declared plastic “a menace to humanity” and subsequently unveiled initial plans to phase out a range of items, including straws, cups and bags. But amid concerns over an economic downturn, the government held off on following through.

Instead, officials said they would seek to encourage Indians to use less plastic voluntarily.

Officials framed an effort to ban plastic waste in Mumbai in 2018 as a test case. But one year on, analysts offered a disappointing assessment. BloombergQuint’s Ashwini Priolker blamed “tardy checks, exemptions to certain items to protect jobs and lack of easy alternatives.”

European Union: Last spring, the European Parliament overwhelmingly voted to ban many single-use plastic items — including plates, straws and cups — by 2021. It also voted to increase recycling targets.

Many E.U. member states already have deposit systems to incentivize customers to return plastic bottles for recycling.

In an interview with German daily Die Welt, new E.U. environment commissioner Virginijus Sinkevicius suggested this month that the union may be open to more bans. “An important step would for example be to ban plastic packaging or to stipulate the use of recycling plastic,” Sinkevicius said.

Malaysia: Developments beyond its control may force the European Union to speed up its decision-making process. Western countries often export much of their plastic waste to Asian countries, including China and Malaysia, to meet their recycling targets.

China threw that approach into disarray in 2017, when it announced it would ban the import of most plastic waste. Other nations in Asia have seen imports surge since the Chinese ban took effect, but the regional recalibration might be short-lived.

Malaysian authorities said this week they had returned 150 containers of what they called illegally imported plastic waste from countries including Britain, France and the United States.

The country’s minister of environment and climate change, Yeo Bee Yin, wrote on Twitter on Sunday that Malaysia would ensure it “does not become the garbage dump of the world.”