Work

Pathways for SDG 6 in Japan: Challenges and Policy Directions for a Nature-Positive Water Future

Year: 2026

Type: article

Abstract: Japan has largely completed the “first half” of SDG 6—universal access to safe drinking water and sanitation—through decades of investment in water supply and sewerage systems, total pollutant load control and stringent regulation of industrial effluents. National indicators show that coverage of safely managed drinking water and sanitation services is close to 99%, and domestic statistics report high achievement rates of BOD/COD-based environmental standards in rivers, lakes and coastal waters [6–11]. At the same time, SDG 6.3.2 (good ambient water quality) remains at 57% and SDG 6.6.1 (extent of water-related ecosystems) shows a −2.8% change in permanent surface water area compared with the 2000–2019 baseline [9,12,13]. The present review synthesizes how far Japan has progressed towards SDG 6, why gaps remain in the “second half” of the goal and which policy pathways are most promising for a nature-positive water future. Using national statistics from the Ministry of the Environment and the Ministry of Land, Infrastructure, Transport and Tourism (1970–2023), UN-Water SDG 6 indicators and recent literature, we map domestic indicators onto the SDG 6 framework, analyse long-term trends in BOD/COD achievement rates and organise remaining challenges using the DPSIR (Drivers–Pressures–State–Impacts–Responses) perspective [2–4,8,9,17,29]. A simple structural break analysis confirms that improvement in BOD/COD achievement essentially stalled around 2002, reinforcing policy concerns that point-source measures alone can no longer deliver additional gains [8,22]. A comparison of SDG 6.3.2 with domestic environmental standard metrics explains why the former is systematically lower: multi-parameter assessment, stricter aggregation rules and greater sensitivity to nutrients and ecological conditions mean that water bodies passing BOD/COD standards may still fail under SDG 6.3.2 [8,9,13]. Building on this diagnosis, the review proposes six strategic directions—climate-resilient water systems, infrastructure renewal and smart asset management, advanced treatment and pollution prevention, integrated water resources management and governance, citizen participation and nature-based solutions (NbS) and green–gray hybrids—and summarises their expected contributions and constraints in a concise overview table [12–14,16,17,24,26]. Finally, we outline how integrated indicator dashboards and, in the longer term, basin-scale simulation platforms (“digital twins”) could help link SDG 6 indicators, domestic statistics and scenario analysis in a transparent, reproducible way [8,9,25,26]. The paper concludes with research and policy priorities for closing the remaining gaps in SDG 6.3 and 6.6 and for advancing towards a nature-positive water future.

Source: Sustainability

DOI: 10.3390/su18020994

Authors: Qinxue Wang, Tomohiro Okadera, Satoshi Kameyama, Xinyi Huang

Institution: University of Tsukuba

Language: English

Topic: Environmental Science and Water Management

Subfield: Water Science and Technology

Field: Environmental Science

Domain: Physical Sciences

SDGs: Clean water and sanitation, Climate action, Sustainable cities and communities, Good health and well-being

Open Access status: gold

Estimated APC paid: $2,896