Plastic pollution in the Ganga river: sources, impacts, and sustainable mitigation strategies in the Himalayan regions

The Ganga River, a critical lifeline for over 400 million people in South Asia, faces severe plastic pollution, with an estimated 0.6 million tons of plastic waste entering its waters annually. This review comprehensively examines the dynamics of plastic pollution in the Ganga basin, focusing on the upper and lower Himalayan regions. It identifies key sources, including tourism-driven waste in the upper Himalayas and urban contributions (70% of the plastic load) in the lower regions, alongside microplastic concentrations ranging from 40 to 100 particles per liter in tributaries like the Alaknanda and Song. Emerging contaminants such as phthalates (10–15 µg/L), heavy metals (lead: 5–10 µg/g), and microbial pathogens (E. coli: 105 CFU/cm2) exacerbate ecological risks, with 60% of fish species ingesting microplastics and the Gangetic dolphin experiencing a 25% population decline over the past decade. Human health impacts include a 10% higher incidence of reproductive issues and over 5000 annual waterborne disease cases, while socioeconomic consequences involve a 20% fisheries decline and $10 million annual cleanup costs in cities like Kanpur. Challenges in assessment, such as inconsistent microplastic sampling and low waste treatment rates (30%), are compounded by weak regulatory enforcement (20% compliance). The review proposes integrated mitigation strategies, including policy reforms like strengthening India’s 2022 single-use plastic ban (targeting 50% waste reduction by 2025), research priorities such as standardizing microplastic protocols, and sustainable practices like biodegradable plastics (60% reduction potential) and waste-to-energy systems (80% efficiency). These recommendations aim to ensure the Ganga’s long-term sustainability, offering a model for addressing plastic pollution in other river systems globally.