Executive Summary:
The Ministry of Environment, Forest and Climate Change addresses concerns regarding industrial effluent pollution in inter-state rivers like the Thenpennai. The Central Pollution Control Board (CPCB), in association with State Pollution Control Boards (SPCBs) and Pollution Control Committees (PCCs), monitors water quality at 4736 locations nationwide. CPCB has directed KSPCB to address sewage/wastewater discharge into the Thenpennai River.
Key Points / Main Content:
Water Quality Monitoring:
* CPCB, SPCBs, and PCCs monitor water quality through the National Water Quality Monitoring Programme (NWMP) at 4736 locations.
* The primary sources of river pollution are sewage from cities/towns and industrial effluent.
* Water quality data is used to identify Polluted River Stretches (PRSs) based on Biochemical Oxygen Demand (BOD) levels.
PRS Identification and Classification:
* PRSs exceeding a BOD limit of 3 mg/L are identified as polluted.
* PRSs are classified from Priority I (most polluted, BOD > 30 mg/L) to Priority V (least polluted, BOD 3-6 mg/L).
* In 2022, 311 PRSs were identified based on 2019-2021 data.
Thenpennai River Pollution:
* The Thenpennai river at Chokkarasanapalli Bridge (Karnataka) and Dakshinak Pinakini river along Mugalur were identified as Priority I, with BOD values of 72 mg/L and 111 mg/L, respectively.
* Water quality assessment for 2024 at Chokkarasanapalli Bridge indicates Dissolved Oxygen (DO) below detection limit (0.3 mg/L), pH ranging from 7.24-8.1, BOD ranging from 17-52.4 mg/L, Fecal Coliform ranging from 280,000-79,000,000 MPN/100 mL, and Total Coliform ranging from 1,600,000-35,000,000 MPN/100 mL.
Action Taken:
* CPCB has communicated to KSPCB in OA No. 1374/2025 before the National Green Tribunal, New Delhi, to address the discharge of sewage/wastewater into the Thenpennai River from Bengaluru and other sources.
Impact Analysis:
KSPCB (Karnataka State Pollution Control Board):
* Impact: Required to address the sewage/wastewater discharge into the Thenpennai River to improve its water quality.
* Action Required: Implement measures to control and treat sewage/wastewater discharge from Bengaluru and other significant sources into the Thenpennai River.
CPCB (Central Pollution Control Board):
* Impact: Oversees and monitors the water quality of rivers and directs SPCBs to take necessary actions.
* Action Required: Continue monitoring water quality and enforce standards for sewage and industrial effluent discharge.
Polluting Industries/Cities:
* Impact: Subject to potential regulatory action if contributing to river pollution.
* Action Required: Adhere to discharge standards for treated sewage and industrial effluent and implement pollution control measures.
Key Entities Referenced
Karnataka: State in India where Chokkarasanapalli Bridge Bangalore is located.
SHRI T R BAALU: Member of Parliament who raised the question in Lok Sabha regarding the discharge of industrial effluents into rivers.
SHRI KIRTI VARDHAN SINGH: Minister of State in the Ministry of Environment, Forest and Climate Change, who provided the answer to the question.
Thenpennai: An inter-state river in Tamil Nadu that is heavily polluted by industrial effluents.
Tamil Nadu: State in India where the downstream stretches of the Thenpennai river are located.
Central Pollution Control Board: A governmental organization responsible for monitoring and regulating pollution in India.
National Water Quality Monitoring Programme: A program under which water quality is monitored at various locations across the country by CPCB, SPCBs and PCCs.
National Green Tribunal, New Delhi: A tribunal in India that deals with environmental issues, where CPCB has communicated to KSPCB regarding sewage discharge into the Thenpennai river.
GOVERNMENT OF INDIA
MINISTRY OF ENVIRONMENT, FOREST AND CLIMATE CHANGE
LOK SABHA
UNSTARRED QUESTION NO. 1335
TO BE ANSWERED ON 28.07.2025
Discharge of Industrial Effluents into the Rivers
1335. SHRI T R BAALU:
Will the Minister of ENVIRONMENT, FOREST AND CLIMATE CHANGE be pleased to
state:
(a) whether the Government is aware that the down stream stretches of many Inter State
rivers like Thenpennai in Tamil Nadu are being heavily polluted by the industrial
effluents locate in upstream stretches; and
(b) if so, the details of deterrent and punitive actions taken by the Central Pollution Control
Board and various Environment Tribunals during the last two years and the current year?
ANSWER
MINISTER OF STATE IN THE MINISTRY OF ENVIRONMENT, FOREST AND
CLIMATE CHANGE
(SHRI KIRTI VARDHAN SINGH)
(a) & (b)
To monitor the pollution of water bodies in the country, Central Pollution Control Board
(CPCB) in association with State Pollution Control Boards (SPCBs) and Pollution Control
Committees (PCCs) has established a Water Quality Monitoring Network under the
National Water Quality Monitoring Programme (NWMP). Currently, water quality
monitoring is carried out at 4736 locations in the country.
The discharge of sewage from cities and towns and industrial effluent is the main source of
pollution of rivers. The Central Government has laid down standards for the quality of
treated sewage and treated industrial effluent to be discharged into rivers and these
standards are enforced by SPCBs.
The water quality data under NWMP is utilized by CPCB for identification of the polluted
river stretches (PRS) based on the level of pollution in terms of the most significant
pollutant – the organic matter content, which is measured in terms of biochemical oxygen
demand (BOD) concentration in the water. All locations/stretches of rivers which are
exceeding the BOD limit (3 mg/L) in the Primary Water Quality Criterion for Outdoor
Bathing are identified as polluted location/ stretches. The PRS are classified from Priority
Class I to Priority Class V, Priority I being most polluted with BOD value of more than 30
mg/L and Priority V being least polluted with BOD ranging between 3 – 6 mg/L.
Based on the above identification and priority classification criteria, CPCB identified 311
PRS in the country during the year 2022 based on water quality data of year 2019 & 2021.
Out of these PRS’s, the Polluted River Stretch/ Polluted River location of Thenpennai river
at Chokkarasanapalli Bridge (Bangalore) in Karnataka was identified as Priority-I withmaximum BOD value of 72 mg/L and PRS of Dakshinak Pinakini river along Mugalur was
identified as Priority-I with maximum BOD value of 111 mg/L.
CPCB – Regional Directorate, Bengaluru monitors water quality of river Thenpennaiyar at
Chokkarasanapalli Bridge at Karnataka-Tamil Nadu inter-state location under National
Water Quality Monitoring Programme (NWMP) on quarterly basis. The assessment of
water quality data for the year 2024 indicates that Dissolved Oxygen (DO) is observed as
Below Detection Limit (BDL) (0.3 mg/ L), pH in the range of 7.24 - 8.1, Bio-chemical
Oxygen Demand (BOD) in the range of 17 - 52.4 mg/ L, Fecal Coliform in the range of
2,80,000 - 79,00,000 MPN/ 100 mL and Total Coliform in the range of 16,00,000 -
35,000,000 MPN/ 100 mL.
With respect to the action taken, it is submitted that CPCB in OA No. 1374/2025 before
the National Green Tribunal, New Delhi has communicated to KSPCB to address the
discharge of sewage/wastewater in river Thenpennai from the Bengaluru city and other
significant sources to improve the water quality of Thenpennai river.
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