Guwahati: A new scientific study has identified specific pollution hotspots inside Deepor Beel, Assam’s only Ramsar wetland, warning that areas near Guwahati’s dumping ground and municipal inflows are experiencing severe water quality deterioration.
Published in the journal Wetlands (2026), the research assessed water samples from ten locations across Deepor Beel during pre- and post-monsoon seasons.
What sets this study apart from earlier assessments is its use of artificial intelligence-based modelling alongside the conventional Water Quality Index (WQI) to not only measure but also predict pollution patterns.
While previous studies mainly reported declining water quality using conventional WQI methods, this research integrates WQI with ensemble machine learning models to forecast water quality trends.
It also identifies specific pollution hotspots near dumping and urban inflow points using AI-based validation and conducts sensitivity analysis to pinpoint the most influential pollutants — such as BOD, COD and TSS — giving policymakers clearer, data-backed priorities for intervention.
The findings show that pollution is not uniform across the wetland. Sites located close to garbage dumping zones and urban discharge points recorded the worst conditions.
Site 8, situated near the municipal waste entry channel, registered a WQI of 105.3 during the pre-monsoon season and 121.7 in the post-monsoon period, placing it firmly in the “polluted” category.
Site 9, near the city’s central dumping ground, remained in the “very poor” category across both seasons, while Site 6 deteriorated sharply after the monsoon, shifting from “poor” to “very poor”.
In contrast, Site 4, located in the central fishing zone of the wetland, maintained “very good” water quality in both seasons, indicating that contamination is concentrated around specific inflow and dumping points rather than spread evenly across the lake system.
The study recorded elevated levels of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total dissolved solids (TDS) and traces of heavy metals such as mercury, cadmium and arsenic in impacted zones. Several parameters exceeded Bureau of Indian Standards (BIS) limits near dumping sites.
A strong negative relationship between dissolved oxygen and pollution levels was also observed, suggesting that rising waste loads are reducing oxygen availability in certain stretches of the wetland.
Beyond measuring contamination, researchers applied Random Forest (RF) and Bagging Random Forest (B-RF) machine learning models to predict water quality trends.
The ensemble B-RF model showed significantly better predictive performance, achieving a correlation coefficient of 0.916 during the post-monsoon season, indicating higher accuracy in identifying deteriorating zones.
Sensitivity analysis further revealed that BOD, COD, TSS, alkalinity, TDS and chloride were the most influential parameters driving water quality decline.
Statistical tests confirmed significant seasonal variation in parameters such as pH, BOD, COD, TSS, nitrate, copper, arsenic and chromium between pre- and post-monsoon periods, pointing to the role of runoff and urban discharge in amplifying pollution loads during the rainy season.
Beyond site-specific findings, the researchers note that the integrated framework used in the study can be applied to other Ramsar wetlands and similar aquatic ecosystems for predictive monitoring and management.
The study calls for urgent interventions to mitigate pollution, including the establishment of functional sewage treatment plants, stricter enforcement of industrial waste management policies, promotion of sustainable agricultural practices, restoration of wetland hydrology, reforestation of buffer zones and removal of invasive species.
It also emphasises community engagement through awareness programmes and sustainable livelihood initiatives as key to ensuring long-term conservation.
Spread over 10.1 sq km in south-west Guwahati, Deepor Beel plays a crucial role in flood buffering, groundwater recharge, and sustaining fishing livelihoods and bird habitats. However, rapid urban expansion, untreated sewage inflow and waste dumping are steadily altering its ecological balance.
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