Comparative policy analysis of urban microplastic pollution and water quality management toward sustainable environmental governance in Malaysian cities

Rapid urbanization in Southeast Asia has intensified microplastic (MP) pollution in city water bodies, urban drainage systems, and coastal environments, posing significant threats to urban water quality and public health. This study employs a comparative policy analysis to evaluate how global, regional, and national legislative frameworks address MP pollution as a critical urban water management challenge, with emphasis on ASEAN member states and Malaysia’s cities. Malaysian urban centres, particularly densely populated coastal cities such as Penang, Kuala Lumpur, and Johor Bahru, exhibit alarming MP contamination across urban water bodies, with reported concentrations ranging from 0.14 particles/L in coastal surface waters to 29,174 pieces/kg in urban sediments — values that reflect two different environmental media (water column versus sediment) and are therefore not directly comparable in magnitude, but together illustrate the pervasiveness of MP contamination across compartments driven by inadequate urban waste management infrastructure and insufficient stormwater governance. Despite Malaysia ranking third globally in marine plastic pollution contributions (73,098 metric tons annually), cities lack dedicated MP-specific urban water management legislation. This governance gap is particularly critical given MP contamination documented across urban Malaysian water bodies and sediments. The study identifies four critical urban governance challenges: (1) legislative fragmentation and weak enforcement in urban environmental management, (2) economic-environmental trade-offs in plastic-dependent urban economies, (3) insufficient municipal solid waste and wastewater infrastructure addressing MP sources, and (4) limited urban public awareness and multi-stakeholder engagement. Through systematic analysis of international regulatory models and ASEAN city-level initiatives, this research proposes an integrated urban environmental governance framework encompassing legislative amendments to the Environmental Quality Act 1974, establishment of city-scale MP monitoring protocols aligned with Sustainable Development Goal (SDG) 11, implementation of Extended Producer Responsibility schemes for urban plastic waste, and enhancement of regional cooperation mechanisms. The findings offer actionable policy recommendations to improve urban water quality, strengthen sustainable municipal solid waste management, and promote resilient and sustainable cities, providing a replicable model for rapidly urbanizing developing nations facing similar urban environmental governance challenges.