The Basel Convention and plastic waste trade

Background: the Basel Convention

The Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal, adopted in 1989 and entering into force in 1992, established the first binding international framework governing the cross-border movement of hazardous and other wastes. Its core principle is prior informed consent: any state wishing to export waste to another must notify and obtain the written consent of the receiving country before the shipment proceeds. For decades, plastic waste sat largely outside the Convention's most stringent controls, classified primarily under Annex IX (non-hazardous recyclable wastes) and therefore subject only to general notification requirements rather than the full prior informed consent procedure.

The practical consequence was that high-income countries — particularly in North America, Europe, Japan, and Australia — exported large volumes of mixed and contaminated plastic waste to lower-income countries in Southeast Asia under the Annex IX classification, nominally for recycling but in many cases without viable downstream processing capacity. China's National Sword policy, implemented in January 2018, abruptly restricted plastic imports to 0.5% contamination tolerance, triggering a crisis in the global plastic waste trade. The volumes previously absorbed by China — estimated at 111 million metric tonnes between 1988 and 2016 — redistributed to Malaysia, Vietnam, Thailand, Indonesia, and the Philippines, rapidly overwhelming their domestic processing capacity.

The 2019 Basel Plastic Waste Amendments

Against this backdrop, parties to the Basel Convention adopted the Plastic Waste Amendments at COP-14 in Geneva in May 2019. The amendments entered into force on 1 January 2021. Their effect was to move mixed, contaminated, or otherwise non-recyclable plastic waste from Annex IX (non-hazardous) to Annex II (other wastes requiring special consideration), placing it under the full prior informed consent procedure. Clean, single-polymer, near-specification plastic waste intended for genuine recycling remained in Annex IX — and therefore continues to flow relatively freely between consenting countries — but the practical difficulty of meeting contamination thresholds has made this a narrower category than it might appear.

The amendments introduced three new entries. Entry B3011 covers clean, uncontaminated plastic waste that is not mixed with other waste types and is destined for recycling in an environmentally sound manner — this stays in Annex IX and remains outside prior informed consent requirements. Entry A3210 covers plastic waste that does not correspond to B3011 — i.e., mixed, contaminated, or non-recyclable plastic — and places this in Annex II, triggering full export controls. Entry Y48 further captures plastic waste not classified elsewhere under the Convention, ensuring the amendments are comprehensive rather than leaving definitional gaps.

The practical effect on major importing countries was significant. The Philippines, Indonesia, Vietnam, and Malaysia each tightened domestic import regulations in 2021 and 2022 to align with their Basel obligations, with Indonesia publishing revised import permit requirements covering all plastic waste categories. Thailand imposed a phased ban on plastic waste imports. These measures substantially reduced the volume of plastic waste crossing borders in the Asia-Pacific region.

Implications for plastic credit markets

The Basel amendments have direct and underappreciated implications for plastic credit projects operating in low- and middle-income countries (LMICs). Many such projects involve the collection of plastic waste — often ocean-bound or post-consumer — in countries including Indonesia, India, the Philippines, and Vietnam. The plastic collected is then baled, sorted, and either processed domestically or sold to off-takers. Where that plastic was previously re-exported — including to China, India, or Turkey — the amendments now require prior informed consent for contaminated fractions.

For corporate buyers of plastic credits, this creates a due diligence obligation that many programs have not yet systematically addressed. A brand purchasing plastic credits from an Indonesian collection project must be able to confirm that: the plastic collected by the project is processed domestically or exported under a compliant prior informed consent procedure; the chain of custody documentation traces the material from collection point to confirmed end processor; and verification body (VVB) site visits have physically confirmed the end processing facility and its capacity. Without this assurance, a credit purchase may inadvertently involve waste that has been re-exported in violation of Basel — a reputational and potentially legal risk for the purchasing brand.

Leading plastic credit standards have begun incorporating Basel compliance into their project requirements. The Verra Plastic Waste Reduction Standard requires project proponents to demonstrate legal compliance in the jurisdiction of collection and to document material end destinations. The Plastic Credit Exchange and rePurpose Global both require project-level chain of custody documentation. However, third-party verification of end-destination claims remains inconsistent, and the audit depth required by different standards varies considerably.

The loophole debate: what counts as recyclable?

A live regulatory debate concerns the interpretation of B3011's requirement that plastic waste be clean, uncontaminated, and intended for genuine recycling. In practice, the boundary between B3011 and A3210 depends on contamination tolerances and the quality of sorting, which vary between assessment methodologies. Some exporters have argued that post-consumer plastic sorted to a reasonable standard qualifies as B3011; critics contend that most post-consumer plastic collected in informal settings cannot reliably meet the contamination threshold without further processing.

The Basel Convention Secretariat has issued technical guidelines on the classification of plastic waste, but these are advisory rather than binding, and national customs authorities apply them with varying stringency. For plastic credit buyers, the practical implication is that a project's legal compliance should be verified by a VVB with on-the-ground presence in the collection country, rather than relying solely on project developer self-reporting.

The UN Plastics Treaty: INC process and credit markets

Simultaneously with the Basel Amendment regime, an entirely new global instrument is under negotiation. In March 2022, the United Nations Environment Assembly (UNEA) adopted resolution 5/14, mandating the development of a legally binding global agreement on plastic pollution, covering the full lifecycle of plastics. The Intergovernmental Negotiating Committee (INC) process began with INC-1 in Punta del Este, Uruguay (November 2022) and has progressed through INC-2 (Paris, May-June 2023), INC-3 (Nairobi, November 2023), INC-4 (Ottawa, April 2024), and INC-5 (Busan, South Korea, November-December 2024).

INC-5 in Busan was widely anticipated as the session that would produce a final treaty text. Negotiations were substantive but did not reach full agreement, with significant divergences remaining on two core issues: whether the treaty should include binding targets to cap or reduce plastic production volumes, and how to address chemicals of concern in plastic formulations. A resumption of INC-5 negotiations is expected in 2025, with ambition to conclude treaty text before the end of that year.

The treaty's relevance to plastic credit markets is substantial. Negotiating blocs including the European Union and the High Ambition Coalition to End Plastic Pollution have supported provisions for National Plastic Reduction Plans — analogous to the Nationally Determined Contributions architecture under the Paris Agreement. If adopted, national plans would create demand for compliance mechanisms, and plastic credits — retired against verified collection and recovery volumes — could emerge as one such mechanism, particularly for countries with nascent formal waste management infrastructure.

Corporate sustainability teams and credit market participants should monitor the ratification timeline and national implementation plans closely. A binding treaty that recognises plastic credits as a compliance tool would significantly expand demand and provide the regulatory legitimacy that the market currently lacks. Conversely, treaty provisions that prohibit credit-based compliance — treating them as a substitute for structural reduction — could constrain the market's growth. The negotiating text as of Busan does not resolve this question definitively.

What corporates should monitor

For corporate buyers of plastic credits and companies running plastic neutrality programs, three developments warrant active monitoring: the conclusion and ratification timeline of the UN Plastics Treaty and its treatment of market-based compliance mechanisms; national implementation of Basel Amendment requirements in key LMIC project countries, particularly Indonesia, India, and the Philippines; and the evolution of VVB audit standards for Basel chain-of-custody verification. Programs that build Basel compliance into their credit procurement now will be better positioned as both the treaty and national regulations mature.