With the bang of a gavel made of recycled plastic and a standing ovation, representatives of 175 nations agreed on Wednesday to begin writing a global treaty that would restrict the explosive growth of plastic pollution.

The agreement commits nations to work on a broad and legally binding treaty that would not only aim to improve recycling and clean up the world’s plastic waste, but would encompass curbs on plastics production itself. That could put measures like a ban on single-use plastics, a major driver of waste, on the table.

Supporters have said that a global plastics treaty would be the most important environmental accord since the 2015 Paris Agreement on climate change, in which nations agreed to cut greenhouse gas emissions. Negotiators are now set to meet this year for the first of many rounds of talks to hammer out the details of treaty on plastics, with a target of sealing a deal by 2024.

“We are making history today,” said Espen Barth Eide, Norway’s climate and the environment minister and president of the United Nations Environment Assembly, which took place for the past week in Nairobi, Kenya. In an earlier interview, he said that, given Russia’s war in Ukraine, it was particularly significant that “this divided world can still agree on something, based on science.”

The sheer volume of plastics the world produces is difficult to comprehend.

By one measure, the total amount ever produced is now greater than the weight of all land and marine animals combined. Only 9 percent has ever been recycled, the United Nations Environment Program estimates. Instead, the bulk is designed to be used just once (recycling symbols are no guarantee of recyclability) after which it ends up in landfills, dumps, the natural environment, or is incinerated.

Scientists say plastics cause harm throughout their life cycle, releasing toxic as well as planet-warming greenhouse gases during production, landfill and incineration. Plastics, which are manufactured from fossil fuels, caused 4.5 percent of global greenhouse gas emissions in 2015, one recent study estimated, more than all of the world’s airplanes combined.

Wednesday’s agreement drew heavily from a joint proposal submitted by Peru and Rwanda, reflecting how, in recent years, developing nations have been at the forefront of efforts to tackle plastics pollution. Rwanda, for example, more than a decade ago adopted strict bans on the import, production, use or sale of plastic bags and packaging.

“Plastic pollution is a planetary crisis, a threat that affects all of us,” Jeanne d’Arc Mujawamariya, the Rwandan environment minister, said at the meeting. “The real work now begins.”

In much of the world, the task of collecting, sorting and recycling plastics often falls to informal waste pickers who work among fires and toxic vapors for little pay. In a landmark move, the agreement in Nairobi for the first time formally recognized the importance of waste pickers in the plastics economy.

“We waste pickers have to be involved in this process,” said Silvio Ruiz Grisales of Bogotá, Colombia, who began working at dump sites at the age of 12. Now he is a leader in the Latin American and Caribbean Network of Waste Pickers, a group that advocates for better pay, working conditions and recognition.

“We work the trash 12, 14 or 16 hours a day,” he said. “It’s a poverty trap.”

Among other requisites, Wednesday’s agreement specifies that any global treaty must be legally binding, and that it must address the full life cycle of plastics, from production to disposal, recycling and reuse. Delegates said they hoped to model the treaty on the Paris climate accord, under which countries set binding targets but are able to meet those goals using a range of different policies.

The treaty must also address packaging design to cut down on plastic use, improve recycling and make technical and financial assistance available to developing nations. According to Wednesday’s agreement, it must also address microplastics, the tiny plastic debris created by the breakdown of plastics over time. Microplastics have been detected by scientists in deep ocean waters, shellfish, drinking water and even falling rain.

In the course of negotiations, some of those points faced objections from countries including the United States, Japan and India, according to three people close to the talks who were not authorized to speak publicly about negotiation details.

Japan had initially submitted a competing resolution focused on marine plastics. India threatened to derail negotiations on the final day, urging that any action needed to be on a “voluntary basis,” according to a list of demands privately submitted by India’s delegation and reviewed by The New York Times.

A reference to concern over chemicals in plastic was taken out of the agreement after objections from delegations including the United States, the three people said. But in a victory for supporters of stronger policies against plastics, Wednesday’s agreement mentions the importance of considering plastic pollution’s risk to human health and the environment.

Monica P. Medina, an assistant secretary of state who heads the American delegation in Nairobi, told delegates that the agreement was “the beginning of the end of the scourge of plastics on this planet.” She added, “I think we will look back on this as a day for our children and grandchildren.”

The Japanese delegate, Yutaka Shoda, ultimately hailed the agreement. “The important thing, is that we are united in developing an international, legally binding instrument,” he said.

The Indian delegation did not respond to requests for comment.

A global plastics pollution treaty would add to existing, albeit limited, global agreements that address trade in plastic waste.

In 2020, more than 180 nations agreed to place limits on exports of plastic waste to poorer countries from richer ones under a framework known as the Basel Convention. The United States has yet to sign on to the new rules, and the Basel Action Network, an environmental watchdog, has said violations are rampant.

Tadesse Amera, an environmental researcher based in Ethiopia and co-chairman of the International Pollutants Elimination Network, a nonprofit group, said a focus on the health and climate effects of plastics was critical. “When we talk about plastics, we’re really talking about chemicals and carbon,” he said.

The role of the private sector — for example, industry’s contribution to the technical and financial assistance to developing nations — is likely to be one big point of debate in the treaty negotiations. In the United States and elsewhere, the cost of recycling is typically borne by cash-strapped municipal governments, as opposed to manufacturers. But there has been a move among environmental groups to require that producers shoulder more of the cost.

“Africa is not a major producer of chemicals or plastics,” Mr. Amera said. But companies are flooding the continent with plastic “with no thought about after-use,” he said. “That should be the responsibility of the producer or importer.”