Assessment of Electric Two-Wheelers: A Narrative Review of Technological Trends, Market Growth, and Policy Drivers Associated with Environmental Concerns

Electric two-wheelers (E2Ws) are key components in decarbonizing urban transportation. Their sustainability implications across different economic contexts remain uneven and are insufficiently synthesized. This review evaluates the sustainability of E2Ws across different economic contexts by synthesizing technological, environmental, market, and policy evidence. Databases such as Scopus, Web of Science, ScienceDirect, and IEEE Xplore were searched for peer-reviewed articles published between January 2015 and September 2025. A structured narrative review approach was applied, and data were synthesized across the technological, environmental, market, and policy dimensions. Studies were categorized according to economic context, including advanced economies (Europe and North America), large emerging economies (China and India), and rapidly motorizing emerging economies (e.g., Vietnam and Southeast Asia). The synthesized evidence focused on battery technologies, regenerative braking systems, charging models, and life cycle sustainability under different electricity mixes. The evidence synthesis found that while E2Ws consistently reduce operational greenhouse gas emissions. Overall sustainability outcomes are strongly influenced by the impacts of battery manufacturing, recycling infrastructure availability, and policy coherence. These findings provide transferable, evidence-based insights to support policymakers and industry stakeholders in accelerating sustainable E2W deployment across both mature and emerging markets.