Environmental Impact Assessment in Southeast Asia



Environmental Impact Assessment (EIA) has been established in Southeast Asia for over 40 years. Each ASEAN Member State, with the exception of Singapore, has a formal and legally binding system of environmental impact assessment for major project that may have a significant environmental or social impact.[1] EIA, as a process of “identifying, predicting, evaluating and mitigating the biophysical, social and other relevant effective of development proposals”, has been adopted by at least 183 jurisdictions as part of their environmental governance systems.[2]

EIA as a process of assessment of the potential impacts of development projects “likely to have a significant impact” on the environment has become increasingly important in ASEAN. As the ASEAN Member States face rapid economic growth, with the associated infrastructure and industrial development, EIA has become a critical tool for promoting sustainable economic growth in the region.[3]

The principles of EIA are clear and many of the elements of EIA procedure are common throughout ASEAN and internationally. EIA has also been consider by the International Court of Justice (ICJ) in relation to the clear obligation under international law to prevent harm to other countries. EIA is to be found in international agreements, such at the Rio Declaration on Environment and Development 1992 (the Rio Declaration) and the Convention on Biological Diversity 1992 (CBD) and the United Nations Convention on the Law of the Sea (UNCLOS).

This article examines the role of EIA and its adoption in ASEAN in the context of the development of an international legal principle on the duty to conduct EIA and the elements that make up an EIA. The conclusion is that the duty to conduct EIA and take into account the issues raised in the EIA, prior to any decision being taken on the project is a clear obligation under international environmental law. It follows that moves to set up systems of project assessment that allow permits or approvals to be given prior to the carrying out of an EIA are in breach of international law.

ASEAN and sustainable development

The ASEAN Charter, which came into force in December 2008, commits the ASEAN community to “ensure sustainable development for the benefits of present and future generations and to place the well-being, livelihood and welfare of the peoples at the centre of the ASEAN community building process.”

One of the purposes and principles contained in Article 1 is:

 To promote sustainable development so as to ensure the protection of the region’s environment, the sustainability of its natural resources, the preservation of its natural resources, the preservation of its cultural heritage and the high quality of life of its peoples.[4]

 The purposes of ASEAN also include:

  • To enhance good governance and the rule of law;
  • To create a single market and production base;[5]
  • The promotion and protection of human rights and fundamental freedoms,[6] and;
  • To promote a people-oriented ASEAN.[7]

Article 2 of the Charter also reaffirms the Principles of ASEAN including, but not limited to, a shared commitment and collective responsibility, non-interference in the internal affairs of ASEAN member States, respect for fundamental freedoms, the promotion and protection of human rights, the promotion of social justice and the upholding of the UN Charter and international law.[8]

Environmental Impact Assessment, environmental protection and sustainable development have been a feature of ASEAN since the Manila Declaration on the ASEAN Environment[9] in 1981. The recognition of EIA as a basis for sustainable development in ASEAN was further acknowledged in the Bangkok Declaration on the ASEAN Environment 1984.[10] The Bangkok Declaration sought to “strengthen the use of EIA process and extended Cost-Benefit Analysis for minimizing the adverse effects and for ensuring proper consideration of environmental values in all projects and programmes under government that are likely to produce significant environmental impact and its gradual extension to the private sector including industry.”[11]

Furthermore the clear recognition of the need to conduct EIA for projects prior to the any decision to approve them found clarity in the drafting of the 1985 ASEAN Agreement on the Conservation of Nature and the Natural Resources (not yet in force), which also identified the role of impact assessment and transboundary EIA.


(1) The Contracting Parties undertake that proposals for any activity which may significantly affect the natural environment shall as far as possible be subjected to an assessment of their consequences before they are adopted, and they shall take into consideration the results of this assessment in their decision-making process.

(2) In those cases where any such activities are undertaken, the Contracting Parties shall plan and carry them out so as to overcome or minimize any assessed adverse effects and shall monitor such effects with a view to taking remedial action as appropriate.

The role and purpose of Environmental Impact Assessment

Environmental Impact Assessment can be defined as:

The process of identifying, predicting, evaluating and mitigating the biophysical, social, and other relevant effects of development proposals (and other activities) prior to decisions being taken and commitments made.[12]

Effective EIA is achieved through the adoption and application of key principles. These include:

  • A legally established clear and effective process;
  • Proponent bears the cost of the application and assessment process;
  • Meaningful public participation at all stage of the process;
  • Access to information by PAP and other stakeholders;
  • All relevant information is available;
  • Open and evidence-based decision-making; and
  • Effective monitoring, compliance and enforcement.[13]

EIA is a process that can be divided into a number of steps. Each step is part of the process. All of the steps must be followed to achieve compliance with the EIA procedures. Although each country does have its own system of EIA, there are a number of similarities.

EIA systems in ASEAN and throughout much of the world generally have most or all of the following steps as depicted in Figure 1 (See Appendix 1). However a more simplified approach to EIA identifies the following six steps as key parts of the EIA process:

  1. Screening
  2. Scoping
  3. Conducting Environmental Impact Assessment and Preparation of EIA Report and ESMP
  4. Review of EIA Report and ESMP
  5. Decision on EIA and EMP
  6. Monitoring and Compliance

Step 1: Screening

The first stage in the EIA process is the screening stage.  Screening is an important part in the EIA process. It is often the first time that the project Proponent will discuss the proposed project with the Government and with the community. The key outcome for the Screening Step is a Screening Report.  Most of the screening lists in the AMS combine these factors in listing projects that require an EIA to be prepared.

Step 2: Scoping

Scoping is an important step in the EIA process. It embodies the process for determining the scope of an EIA (i.e. the data that need to be collected and analyzed to assess the potential adverse impacts of a project) and producing a terms of reference (ToR) for preparation of an EIA Report.

Step 3: Preparation of the EIA

Once the Scoping Report and Terms of Reference have been approved by the relevant EIA Authority, or finalized by the EIA Consultant, the task of gathering the information and preparing the EIA Report commences. This can take between three months and three years depending on the type of project and the environmental and social issues that must be addressed.

Based on the information gathered, the EIA Consultant will prepare the EIA Report. An Environmental Management Plan (EMP) must be prepared for the Project. The EMP should be presented in a separate volume annexed to the EIA Report. It should be developed for each stage in the Project as required: Pre-construction, construction, operation, closure, decommissioning and rehabilitation.

Step 4: Review and Assessment of the EIA

The decision on whether to approve, require amendments to, or reject outright an EIA ultimately rests with government. This is a decision that should be made independently, transparently and on the basis of complete information and scientific evidence. Accordingly, a clear review process, involving opportunities for public participation, is required.

Step 5: Approval of the EIA Report

The decision on whether to approve, require amendments to, or reject outright an EIA ultimately rests with government. This is a decision that should be made independently, transparently and on the basis of complete information and scientific evidence.

Once a decision is made on the EIA, the public and proponent should both have access to an appeals process. For the appeals process to be effective and trusted, the decision must be publicly released along with the reasoning. Following the approval of the EIA Report, the Project will usually be required to obtain all other approvals and permits, including any foreign investment approvals.

Step 6: Monitoring and Compliance

For projects that have an EIA approved and proceed to implementation, it is vital both for the environmental and social outcomes and for the integrity of the EIA system that the project construction, operation and eventual decommissioning comply with the EIA, EMMP and any conditions of approval.

Monitoring is a continuous activity. Monitoring will help the satisfy the community that the project is being operated in accordance with the conditions of approval. It also helps to respond to issues and concerns before serious consequences occur.

A recent Compendium prepared by UNEP to the ASEAN Intergovernmental Commission on Human Rights (AICHR)[14], examined the EIA regimes in ASEAN member states[15], the Mekong River Commission, and the international instruments in the Economic Commission for Europe[16] and Economic Commission for Latin American and the Caribbean[17]. The Compendium identified many commonalities on the key elements of EIA across ASEAN. Although Singapore lacks a legislative basis for EIA, it is carried out based on specific projects and broadly conforms to the requirements for EIA adopted by other countries in ASEAN.

ASEAN countries provide for access to information, public participation and access to remedies, including grievance redress mechanisms and other project specific complaints processes. These are important procedural rights that are necessary to ensure that EIA can be effective and identify community concerns about development projects. These procedural mechanisms also ensure that the human rights obligations to a safe, clean and safe environment are protected.[18]

Table 1

Table 1: Common elements of EIA systems (Green is clearly present, Yellow is partially present, Grey is not present). MRC refers to the Mekong River Commission, ECE is the Economic Commission for Europe and ECLAC is the Economic Commission for Latin American and the Caribbean.

Whilst the EIA process itself shares many similarities across the AMS, there are also country specific differences. EIA itself has evolved with a number of conferences and workshop looking at measures to strengthen the value of the EIA process.[20] In addition to the examination of ways to enhance the EIA process itself, there is considerable discussion about the application of the EIA principles to the assessment of the transboundary impacts of development. New tools such as Strategic Environmental Assessment (SEA) have been developed to examine the environmental and social impact of proposed plans, policies and programmes.

The EIA process also relies on the need for meaningful public participation to ensure those communities and groups who many be impacted by a project or plan have the opportunity to be consulted and make comments on the project, and to have those comments considered by the decision-maker. Meaningful public participation also requires timely disclosure of all relevant information, whether in the possession of the government or the project proponent (or EIA consultant engaged by the project proponent). Information relevant to the project must be disclosed in a manner and form that gives the project affected people (PAP) and other stakeholders enough time to consider that information and make comments or raise issues. These issues and comments need to be addressed and the PAP informed about the responses as part of a meaningful process of public participation.


EIA under international law

Since the beginning of the formal role of environmental assessment in the 1970s, the concept of prior assessment of environmental and social impacts of project likely to have a significant effect on the environment has entered into almost universal application. The requirement that EIA be undertaken prior to any decision to approve a project has been recognised as a principle of international law by the International Court of Justice (ICJ) since the case of Argentina v Uruguay (2010) and this was reaffirmed in the case of Costa Rica v Argentina (2015). In both of these court cases the ICJ that EIA in the transboundary case was a binding norm of international law.[21]

Principle 17 of the Rio Declaration on Environment and Development 1992, states:

 Environmental Impact Assessment, as a national instrument, shall be undertaken for proposed activities that are likely to have a significant adverse impact on the environment and are subject to a decision of a competent national authority.[22]

Reflecting the provisions of Principle 17 of the Rio Declaration, the ICJ in Costa Rica v Argentina (2015), made clear that each state had the ability to determine the content of the EIA in light of the specific national legislation. But, if the requirements for an EIA had been triggered by such a law, or the international legal obligation, the EIA needs to be undertaken “before embarking” on the activity or project.[23] The ICJ also found that the obligations of notification and consultation in good faith were fundamental elements of the EIA process. Following this process of assessment of the risk of harm, it was also an obligation to “determine appropriate measures to prevent or mitigate that risk”. [24]

The ICJ was clear in both Argentina v Uruguay (2010)(The Pulp Mills Case) and in Costa Rica v Argentina (2015), that the obligation to conduct an EIA for a particular project must be fulfilled prior to the implementation of the activity or project.[25] The ICJ also found that the obligation to mitigate environmental harm in the transboundary context was an ongoing one and continues during the construction of the activity (in this case a road) and during the operation of the activity.

 Table 1 above shows the common elements in EIA in ASEAN. In a recent review of EIA worldwide, Tseming Yang confirmed that the six EIA steps listed above provided a common EIA framework. In addition, the elements of public consultation and the provision of information to potentially affected people (PAP) were also almost universally applied. This review identified that only six countries had not incorporated EIA into existing laws on environmental governance.[26]

Above all the obligation to conduct EIA prior to any decision to approve a project or activity, and to ensure that the EIA considers both the potential impact of the activity and any steps to avoid or mitigate the environmental and social impact, accords with all other international legal obligations. Reference to EIA can also be found in the UN Convention on the Law of the Sea, the Convention on Biological Diversity, and the Rio Declaration as well as many other regional and multi-lateral treaties. This is also clearly stated in Article 14 of the ASEAN Agreement on the Conservation of Nature and the Natural Environment 1985.


Challenges to EIA

In a time of increasing development pressure within Southeast Asia, especially with respect to the infrastructure development boom through the Belt and Road Initiative (BRI) and following the COVID-19 impacts on economies, there are many moves to wind back environmental and social governance. In some countries there has been a move to minimise the requirement for EIA, or to allow project to obtain approvals before finalising the EIA process.[27] Many governments are seeking to review and speed-up foreign direct investment to provide a possible kick-start to economic development feeling the impacts of the Covid-19 crisis. The temptation to amend or reduce the obligations for good EIA must be rejected. Not only would this be in breach of international, it would also significantly impact on the ability of countries to build strong and resilient economies that will be able to withstand the future-shock of climate change and natural disasters.

EIA provides a unique legal mandated opportunity to ensure that major projects, including infrastructure projects, assess potential environmental and financial risks and avoid or mitigated those risks. The recent example of the East-West Rail link in Malaysia (a 600-kilometer electrified line will connect Kuala Lumpur with Kelantan through the rural states of Pahang and Terengganu) is an example of the value of environmental assessment and risk management. Following the Malaysian elections in 2019, the already approved project was put on hold. After a review, the layout of the project was altered, to protect a highly significant area of the Central Forest Spine, a biodiversity hotspot. The review also reduced the cost of the project by a staggering 30%, saving the Malaysian Government RM20 billion (US$4 billion).[28] This project demonstrates the importance of the ongoing process of EIA especially for large scale infrastructure projects. Good, professional, prior EIAs can contribute to the financial viability and environmentally sustainability of all projects.

Governments should take the opportunity from the COVID-19 crisis to re-commit to the core principles of EIA and to promote the objectives of the ASEAN Charter to promote “sustainable development so as to ensure the protection of the region’s environment, the sustainability of its natural resources, the preservation of its natural resources, the preservation of its cultural heritage and the high quality of life of its peoples.”[29]

 Annexure 1

Overview of EIA Process

Figure 1: Overview of Environmental Assessment Process.[30]


Legal Instruments

Rio Declaration on Environment and Development, Rio de Janeiro, 14 June 1992.


Trail Smelter Arbitration (US v Canada), 3 RIAA (1941) 1905

Pulp Mills on the River Uruguay (Argentina v Uruguay) [2010] ICJ Rep 14

Certain Activities Carried Out by Nicaragua in the Border Area (Costa Rica v Nicaragua) and Construction of a Road in Costa Rica along the San Juan River (Nicaragua v Costa Rica) (Judgment) [2015] ICJ Rep 665


[1] Singapore has a system of environmental assessment for major projects but this system is not formally enacted in a law or regulation.

[2] Tseming Yang (2019) at 527

[3] IGES (2016), p. i.

[4] ASEAN Charter Article 1(9) (Emphasis added)

[5] Article 1(5)

[6] Article 1(7)

[7] Article 1(13)

[8] Article 2(2).

[9] Manila 30 April 1981, Koh p.653

[10] Bangkok Declaration of the ASEAN Environment 29 November 1984, Koh (2009), p.657

[11] Koh (2009), p.658

[13] Baird (2018)

[14] Baird (2018)

[15] See also ONEP (2018)

[16] Including the Arhus Convention, the Espoo Convention and the Kyiv Protocol

[17] Including the Regional Agreement on Access to Information, Participation and Justice in Environmental Matters in Latin America and the Caribbean (the Escazu Agreement) (not yet in force)

[18] See in particular the reports by the Special Rapporteur on Human Rights and the Environment by Professor John Knox in Knox (2013) and Knox (2018)

[19] The MRC applies the Prior Notification, Prior Consultation and Approval process for major projects that will impact the Mekong River Basin. This includes Transboundary environmental assessment and public consultation.

[20] IGES (2016)

[21] Tseming Yang (2019), p,533

[22] Principle 17 of the Rio Declaration on Environment and Development, 1992.

[23] Costa Rica v Nicaragua (2015), [104]

[24] Costa Rica v Nicaragua (2015), [104]

[25] Costa Rica v Nicaragua (2015), [106]

[26] Tseming Yang (2019), p.560.

[29] ASEAN Charter Article 1(9) (Emphasis added)

[30] Baird and ERI (2016), p.29.


Baird (2018) ASEAN Intergovernmental Commission on Human Rights thematic study on commonalities in EIA in ASEAN Member States, Study Commissioned by UNEP, 2018.

Baird (2019) Compendium on Environmental Impact Assessment in the ASEAN Member States, UNEP, 2019.

Baird and ERI (2016)   EIA in the Mekong Region, Materials and Commentary, Edited Matthew Baird and Earth Rights International, Published by Earth Rights International, 2016.

IGES (2016) Sano, D, Matsumoto, I, Urago, A, Takahashi, Y, and Genjida N, 2016. Strengthening EIA in Asia, Institute for Global Environmental Studies, Japan

Knox (2013). Report of the Special Rapporteur on the issue of human rights obligations relating to the enjoyment of a safe, clean, healthy and sustainable environment, A/HRC/31/53, 2015

Knox (2018), Framework Principles on Human Rights and the Environment, http://srenvironment.org/2018/01/24/framework-principles-on-human-rights-and-the-environment/

Koh (2009). Koh Kheng-Lian, ASEAN Environmental Law, Policy and Governance, Selected Documents, Vol. 1, World Scientific Publishing, Singapore. 2009

ONEP (2018).  EIA Guidelines for Business Project Development in ASEAN Economic Community, Office of Natural Resources and Environmental Policy and Planning, Ministry of Natural Resources and Environment, Thailand, 2018.

Tseming Yang (2019), The Emergence of the Environmental Impact Assessment Duty as a Global Legal Norm and General Principle of Law, Hastings Law Journal Volume 70:525 at 527 (February 2019)