Environmental Policy Implementation and Communication in the Association of Southeast Asian Nations Manufacturing: A Comparative Case Study of Three Key Manufacturing Firms in Indonesia, Malaysia, and Thailand (2020–2023)

ASEAN’s manufacturing sector contributes significantly to economic growth but also presents major environmental challenges. This study investigates how environmental policies are implemented by three leading manufacturing firms in Indonesia, Malaysia, and Thailand, focusing on their alignment with ASEAN’s regional guidelines. A qualitative document analysis was conducted, examining sustainability reports, annual reports, and corporate policy statements to identify patterns and gaps in environmental strategies. The findings reveal that Sime Darby (Malaysia) and PTT Global Chemical (Thailand) exhibit stronger alignment with ASEAN guidelines, particularly in renewable energy adoption and biodiversity conservation. In contrast, PT Astra International (Indonesia) prioritizes emissions reduction and waste management. These differences reflect the influence of national policies and institutional settings on corporate strategies. This study offers practical insights into regional gaps and proposes standardizing KPIs, enhancing cross-border collaboration, and promoting green innovation. This research provides a comparative perspective on corporate environmental practices in ASEAN, offering practical recommendations for standardizing Key Performance Indicators, fostering regional collaboration, and encouraging green innovation. An integrated ASEAN-wide policy framework is needed to support environmental sustainability in the manufacturing sector.