Once the lifeline of Dhaka city, the Buriganga River today resembles a vast black drain. Its waters, thick with industrial sludge and untreated sewage, emit a stench that spreads across neighborhoods. Despite the arrival of monsoon rains that typically refresh rivers elsewhere, the Buriganga continues to suffocate. The seasonal floods may dilute the filth, but they do little to restore the ecological balance.
On the occasion of World Rivers Day, observed on the last Sunday of September, new research conducted by the Center for Atmospheric Pollution Studies (CAPS) has drawn renewed attention to the catastrophic state of this historic river. The study provides perhaps the most detailed seasonal analysis yet of the Buriganga’s pollution levels-and the results are alarming.
A Year-Long Study Reveals a River in Distress: Between 2022 and 2023, CAPS conducted a comprehensive study of the Buriganga, sampling water at eight points-Mirpur Bridge, Basila Bridge, Hazaribagh, Kamrangir Char, Chandnighat, Sadarghat, Dholai Khal, and Postogola Bridge-over six seasons across 12 months.
The team measured 10 key parameters: dissolved oxygen (DO), biochemical oxygen demand (BOD), visibility, electrical conductivity, temperature, pH, turbidity, alkalinity, total suspended solids (TSS), and total dissolved solids (TDS). The results were then compared to the national environmental quality standards outlined in the Environmental Conservation Rules 2023.
According to CAPS founder and chairman, Professor Dr. Ahmad Kamruzzaman Majumder, who led a 15-member research team: “The Buriganga lost its natural vigor in the 1990s. It is now a river of pollution. Every day untreated sewage and industrial waste are released into it. Through this study we wanted to understand the seasonal variations of pollution and the real character of the river’s water quality.”
The findings point to a grim reality: while monsoon offers temporary relief, pollution peaks to dangerous levels in spring and winter, making large stretches of the river biologically uninhabitable for aquatic life.
Oxygen Deficiency: A Death Sentence for Aquatic Life: The most critical parameter for any river ecosystem is dissolved oxygen. Aquatic organisms require at least 5 milligrams per liter (mg/L) to survive. But in the Buriganga, the CAPS study found average dissolved oxygen levels across six seasons and eight points to be just 3.01 mg/L. Except during monsoon (6.55 mg/L) and autumn (6 mg/L), oxygen levels remained critically low. In winter, the average plunged to a shocking 0.63 mg/L-conditions under which fish and most aquatic organisms cannot survive.
Experts explain that monsoon rains help flush the river, bringing in oxygenated water and diluting pollutants. But during the dry months, lack of rainfall, combined with heavy sewage and industrial discharges, turns the river into a biological dead zone.
Biochemical Oxygen Demand: Pollution 18 Times Higher Than Standard: Another key indicator, Biochemical Oxygen Demand (BOD), measures the amount of oxygen required by microbes to decompose organic matter in water. For aquaculture, the permissible limit is 6 mg/L, while even treated wastewater should not exceed 30 mg/L.
In the Buriganga, however, CAPS recorded an average BOD of 107.94 mg/L-a staggering 18 times higher than the acceptable threshold. During spring, the worst season, BOD levels soared to 217.50 mg/L, 36 times the limit. Even during monsoon, when water quality improves, BOD was 24.38 mg/L, still too high for safe fish cultivation.
“These numbers show that none of the Buriganga’s sites are suitable for aquaculture,” observed CAPS researchers.
Transparency Lost: The Black Waters of Dhaka: Once clear enough to reflect the city’s skyline, the Buriganga’s water has turned so opaque that visibility rarely exceeds a few inches. In autumn, when pollution levels slightly drop, average visibility across sample sites was 22 inches, with Basila, Hazaribagh, and Sadarghat reaching over 25 inches.
But during spring, visibility was reduced to just 9 inches-a clear indication of heavy suspended particles and filth dominating the river.
Other Alarming Indicators: Electrical Conductivity (EC): Pure water has low conductivity. But in the Buriganga, EC reached 917 microsiemens per centimeter in spring, reflecting high dissolved salts and pollutants. The lowest reading (182) came during monsoon, but levels remain within the tolerable limit of 1,200.
Temperature: Seasonal variations ranged from 23.13°C in winter to 29.32°C in summer, within regulatory limits but stressful for aquatic ecosystems when combined with low oxygen. Averaging 7.73, the Buriganga’s water remains within acceptable limits for fisheries and industrial use (6-9), though this offers little consolation given other toxic conditions.
Suspended Solids: Dholai Khal recorded the highest Total Suspended Solids (TSS), far exceeding standards. This indicates direct dumping of untreated waste, including polythene and solid garbage.
Expert Voices: Can Buriganga’s Lost Youth Return: The findings have reignited debate among environmental experts about whether the Buriganga can ever be restored.
Dr. Ainun Nishat, Emeritus Professor at BRAC University and one of Bangladesh’s leading climate and water resource specialists, drew parallels with the River Thames in London, which was once declared biologically dead but later revived.
“The Buriganga’s main problem is untreated liquid and solid waste from factories. If these are properly treated with modern systems, water quality will improve drastically. Secondly, the Buriganga once received water from the Brahmaputra and, centuries earlier, from the Ganges. Even 50 to 100 years ago it was fed by the Jamuna. Restoring that water flow could help flush the river. Thirdly, dredging and removing the waste from the riverbed to increase depth and width is essential. Only by combining these three steps can we bring the Buriganga back to life.”
But not all experts are optimistic: At a recent seminar at North South University, Syeda Rizwana Hasan, Adviser to the interim government’s Ministry of Environment, Forest and Climate Change, acknowledged the challenges. She revealed that Bangladesh is negotiating with the World Bank for a project to revive four rivers around Dhaka-Turag, Balu, Shitalakkhya, and Dhaleshwari-but Buriganga is not included. “The Buriganga’s problem is very complex. Dredging alone will not solve it. The riverbed contains thousands of tons of polythene. Even if you remove them, what will you do with the waste? Finding a solution within the next one and a half years is impossible.” Her remarks underscore the scale of the crisis.
World Rivers Day: A Reminder Amid Despair: As Bangladesh joins the global community in marking World Rivers Day, the state of the Buriganga serves as a grim reminder of how unchecked industrialization, poor urban planning, and weak enforcement can destroy a natural resource.
The Daily Industry notes that despite decades of promises, rivers around Dhaka continue to be treated as open drains for the city’s waste. The Buriganga, once a mighty channel that carried the heritage of the Ganges and the Brahmaputra, has been reduced to an environmental tragedy.
Between Hope and Hopelessness: The Buriganga’s condition represents not just environmental neglect but also the failure of governance. While experts point to feasible solutions-industrial waste treatment, restoring natural flows, and dredging-the absence of political will and coordinated planning keeps the river trapped in its cycle of decay. For residents of Dhaka, the black waters of the Buriganga are a daily sight and smell. For environmentalists, it is a national shame. And for policymakers, it remains a “complex problem” deferred year after year. The question now is stark: Will Buriganga ever is reborn, or will it remain the river of death flowing past the heart of Bangladesh’s capital?
