Mapping Inter-State Rice Virtual Water Trade in India Using Complex Network Analysis

Inter-state agricultural trade plays a critical role in redistributing water resources across India, particularly for water-intensive crops such as rice. This study examines the structure of inter-state rice virtual water trade in India using a directed, weighted complex network approach. Physical inter-state rice trade data covering all Indian states were obtained from the Directorate General of Commercial Intelligence and Statistics (DGCIS) and transformed into virtual water flows using crop-specific virtual water content coefficient for rice (m³/ ton), assumed to be uniform across states. This transformation enables an assessment of trade relationships in terms of embodied water transfers rather than physical commodity volumes. States are represented as nodes and directed edges denote rice virtual water flows from exporting to importing states, weighted by total virtual water volumes (m³). Network properties were analysed using strength-based measures to quantify import and export intensities, betweenness centrality to identify states functioning as key intermediaries in trade pathways, and PageRank to assess systemic importance within the national virtual water trade system. These metrics jointly allow differentiation between dominant exporting states, import-dependent states, and structurally central states influencing the overall redistribution of water through trade. The analysis reveals a highly centralized rice virtual water trade network, characterised by a small group of states accounting for a disproportionate share of total virtual water exports. States such as Punjab, Haryana, Andhra Pradesh, Chhattisgarh, Uttar Pradesh, Odisha, and Madhya Pradesh emerge as major exporters, while several other states rely predominantly on inter-state imports to meet rice demand. The concentration of virtual water exports among a limited number of producing regions indicates strong structural dependencies within the national trade network. Several major exporting states like Punjab are also subject to increasing pressure on water resources, the observed trade patterns raise concerns regarding the sustainability of current production-trade configurations. By integrating crop-specific virtual water accounting with complex network analysis, this study provides a quantitative framework for identifying key contributors, dependencies, and structural vulnerabilities in India’s inter-state agricultural water redistribution system. The methodology is transferable to other crops, years, and regional contexts and offers a basis for informing discussions on sustainable agricultural trade and water resource management.