Bengaluru: Water quality in the Cauvery river has emerged as a major concern, with samples from parts of Bengaluru falling under the E category in the Karnataka State Pollution Control Board’s (KSPCB) August 2026 assessment.
The Cauvery is one of the major sources of water for southern Karnataka and is also known as Dakshina Pinakini. The latest KSPCB classification indicates significant pollution at several monitoring locations, particularly in Bengaluru.
According to the Central Pollution Control Board (CPCB) classification, E category is the lowest of the five designated-use categories and indicates that water is suitable for irrigation, industrial cooling and controlled waste disposal. It is not classified as suitable for drinking or organised bathing without appropriate treatment.
Cauvery classified as E at two Bengaluru locations
The KSPCB’s Water Quality Classification of Polluted River Stretches in Karnataka for August 2026 placed Cauvery water under the E category at Sarjapur and Mahadevapura in Bengaluru.
The same assessment found the river in different categories at other locations. In Chamarajanagar, Mandya and Ramanagara, the water quality was classified under C and D categories, according to the report.
Under the CPCB classification, C category denotes a water source that can be used for drinking after conventional treatment followed by disinfection. D category is designated for propagation of wildlife and fisheries.
The classifications are based on the designated best use of water and do not mean that water from a particular river can be consumed directly without treatment.
None of monitored sources in A category
The KSPCB’s April-August 2026 monitoring covered several major rivers and reservoirs across Karnataka.
The rivers included the Tungabhadra, Cauvery, Kabini, Krishna, Bhima, Ghataprabha, Malaprabha, Bhadra, Hemavathi, Kali, Karanja, Yagachi, Netravathi, Kumudavathi, Kumaradhara, Arkavathy, Lakshman Tirtha, Kagina, Asanganalla and Shimsha, among others.
Water quality was also monitored at reservoirs including Almatti, Vanivilasa Sagara, Rakkasakoppa, Sumavathi and Gundal at different locations.
The August report showed that the Arkavathy river at Rajarajeshwari Nagar in Bengaluru Urban and locations in Ramanagara were classified under E. The Arkavathy was listed as the most polluted among the stretches covered in the assessment.
The report stated that water quality at all the monitored locations was classified as C or below.
None of the monitored sources was listed under A category.
What the five water categories mean
The CPCB’s designated-use classification divides water quality into five categories based on the best use for which the water can be utilised.
A category: Drinking water source without conventional treatment but after disinfection.
B category: Water suitable for organised outdoor bathing.
C category: Drinking water source requiring conventional treatment followed by disinfection.
D category: Water suitable for propagation of wildlife and fisheries.
E category: Water suitable for irrigation, industrial cooling and controlled waste disposal.
The classification therefore provides an indication of the quality and designated use of a water source at a particular monitoring location.
Kodagu samples show better classification
The KSPCB’s April-July 2026 report also showed variations in Cauvery water quality along different stretches of the river.
Samples collected at five locations in Kodagu were classified under B category. Under the CPCB classification, B category water is suitable for organised outdoor bathing.
The variation in classification between monitoring points indicates that water quality differs across stretches of the river and is influenced by local conditions and pollution sources.
The findings also highlight the difference between water quality at the upper reaches and locations closer to heavily urbanised areas.
KSPCB official raises concern
A senior KSPCB official, speaking on condition of anonymity, said that nearly all water bodies in Karnataka, including lakes and rivers, fall under the D category.
The official said that even if all installed sewage treatment plants around water bodies operate at full capacity and pollution sources are stopped, improving and restoring water quality would take considerable time.
The observation points to the long-term nature of restoring polluted water bodies, particularly where sewage and other pollutants have entered water systems over an extended period.
Minister seeks detailed reports
The water-quality concerns have also come amid proceedings before the National Green Tribunal relating to pollution in the Cauvery.
Forest, Environment and Ecology Minister Ramalinga Reddy said he had sought detailed reports from the KSPCB, Bangalore Water Supply and Sewerage Board and the Water Resources Department regarding the condition of the river.
According to the information available, the departments had not submitted the requested reports at the time of the minister’s statement.
Reddy acknowledged that the water quality was poor and said stringent action should be taken against officials and polluters responsible for allowing pollution to continue.
The KSPCB assessments, meanwhile, show that the condition of the Cauvery varies considerably between monitoring locations, with some stretches falling into categories that restrict their designated use.
The latest findings underline the need for continued monitoring, treatment of sewage and control of pollution sources along the river and its tributaries. Further action by the state authorities is expected to depend on the detailed reports sought from the concerned departments and the ongoing proceedings concerning the river’s water quality.