Barriers for integration of green energy in electric vehicles and future perspectives for South Asian countries: A systematic review

The global transition toward sustainable transportation depends on the successful integration of renewable energy sources with electric vehicle (EV) charging systems. In South Asia a region shaped by rapid urbanisation, heavy fossil fuel import dependence, and worsening urban air quality this integration remains critically underdeveloped despite significant policy commitments. This systematic review, guided by PRISMA 2020 guidelines, examines the barriers that prevent green energy-EV integration across five key South Asian economies: India, Pakistan, Bangladesh, Sri Lanka, and Nepal. Unlike prior reviews that treat EV adoption or renewable energy deployment as separate concerns, this study is the first to apply a unified cross-country comparative framework specifically to the green energy-EV nexus in South Asia, delivering insights that country-level or general developing-country studies cannot provide. Country-specific findings show that India leads in deployment scale while Pakistan holds the greatest untapped renewable potential, yet both are held back by persistent structural problems such as grid instability, fragmented regulatory frameworks, high capital costs, and weak coordination between ministries. Nepal’s hydro-EV model and Sri Lanka’s experience with policy reversals offer contrasting paths that reveal both the opportunities and the pitfalls of green transport transitions in low- and middle-income settings. A frequency-weighted barrier severity scoring system, drawing on evidence counts from the reviewed literature, is used to rank barriers across countries. The review also acknowledges that cross-country comparisons are complicated by structural differences in GDP, population density, and institutional capacity, and a dedicated limitations section is included to address these confounding factors. The findings carry direct implications for policymakers, energy regulators, and development finance institutions working toward nationally determined contributions (NDCs) and the Sustainable Development Goals (SDGs).