National Green Tribunal
National Green Tribunal Southern Zone vs Tamil Nadu Pollution Control Board ... on 7 November, 2025
Item No.13:-
BEFORE THE NATIONAL GREEN TRIBUNAL
SOUTHERN ZONE, CHENNAI
Friday, the 07th day of November, 2025.
[Through Physical Hearing (Hybrid Option)]
Original Application No.29 of 2025 (SZ)
[Earlier O.A. No.1365 of 2024 (PB)]
IN THE MATTER OF
Tribunal on its own motion SUO MOTU based on the
news item in Hindustan Times dt. 06.12.2024 titled
"3 dead due to 'contaminated drinking water'
near Chennai" and news item in The Times of India
dt. 07.12.2024 titled "Pathogens to watch out for:
Taps near sewage lines could be behind
Chennai contamination deaths"
With
1. Tamil Nadu Pollution Control Board
Through its Member Secretary,
No.76, Mount Salai, Guindy,
Chennai - 600 032.
2. Central Pollution Control Board
Through its Member Secretary,
Parivesh Bhawan, East Arjun Nagar,
Delhi - 110 032.
3. Tamil Nadu Water Supply and Drainage Board
Through its Managing Secretary,
No.31, Kamarajar Salai,
Chepauk, Chennai - 600 005.
4. Ministry of Environment, Forests & Climate Change
Through its Regional Officer,
Integrated Regional Office,
1st Floor, Addl. Office Block for GPOA,
Shastri Bhavan, Haddows Road,
Nungambakkam, Chennai - 600 006.
5. District Magistrate,
Chennai, Fourth Floor,
M. Singaravelar Maaligai,
62, Rajaji Salai,
Chennai Collectorate,
Chennai - 600 001.
6. Tambaram City Municipal Corporation
Represented by its Commissioner
28, Muthurengam Street,
West Tambaram, Chennai - 600 045.
(R6 - Suo Motu impleaded as per order dt.10.02.2025.)
...Respondent(s)
Page 1 of 12
For Applicant (s): Suo Motu.
For Respondent(s): Mr. S. Sai Sathya Jith for R1.
Mr. D.S. Ekambaram for R2.
Mrs. Y. Kavitha for R3.
Mr. Sai Srujan Tayi for R4.
Dr. D. Shanmuganathan for R5.
Mr. P. Srinivas for R6.
Judgement Reserved on: 18th September, 2025.
CORAM:
HON'BLE Smt. JUSTICE PUSHPA SATHYANARAYANA, JUDICIAL MEMBER
HON'BLE Dr. PRASHANT GARGAVA, EXPERT MEMBER
JUDGMENT
Delivered by Smt. Justice Pushpa Sathyanarayana, Judicial Member
1. The above-captioned matter was suo motu registered by the Principal Bench of the National Green Tribunal, New Delhi, based on a news item published in Hindustan Times dated 06.12.2024 titled "3 dead due to 'contaminated drinking water' near Chennai" and also a news item in The Times of India dated 07.12.2024 titled "Pathogens to watch out for: Taps near sewage lines could be behind Chennai contamination deaths".
2. The incident involves the death of three individuals and the hospitalization of twenty others in Tambaram, near Chennai, Tamil Nadu, allegedly due to contaminated drinking water. According to news reports, a pair of public taps located near a sewage line on the narrow Mariamman Koil Street are suspected to be the primary sources of the contamination. Water samples collected from five locations in the Pallavaram Cantonment area and five sites in Pallavaram Kamarajar Nagar, both under the Tambaram Corporation, have been sent for testing to determine the exact cause of the fatalities.
Page 2 of 123. Residents have reported symptoms such as diarrhoea and nausea, and have complained of a foul odour in the water. It is further noted that the area has been grappling with contaminated water issues for the past fifteen years.
4. The news report also alleges that the water pipeline may have sustained damage during Cyclone Fengal, potentially allowing sewage to infiltrate the water supply. Additionally, it is mentioned that approximately 50 households in the vicinity, primarily lower-income families, rely on these public taps for water, which is supplied by the Tamil Nadu Water Supply and Drainage (TWAD) Board sourcing from the Palar River and local groundwater wells. A Metro water tanker also delivers water to the area once every two days.
5. Considering the gravity of the issue, the Principal Bench, New Delhi initially registered it as Original Application No.1365 of 2024 (PB). The case was later transferred to this Bench, where it was renumbered as Original Application No. 29 of 2025 (SZ).
6. Upon notice, the respondents have entered appearance through their counsels and filed their respective pleadings.
7. Respondent No.1, the Tamil Nadu Pollution Control Board (TNPCB) has filed its report dated 04.03.2025, stating that the areas of Pallavaram, namely Mariammankoil Street, Muthalamman Street, Malamedu Street, Ward-13 Kamaraj Nagar, Kannabiran Koil Street, Munnusamy Street, Ambedkar Street, PP Amman Koil Street, and the Pallavaram Cantonment Board area, fall within the jurisdiction of Tambaram City Municipal Corporation (TCMC), Chengalpattu District. The Board officials inspected these locations on 08.12.2024 and observed that the said areas are densely populated with residential houses and commercial establishments. As reported by the TWAD Board, approximately 10.00 MLD of drinking water is supplied to the Tambaram City Municipal Corporation from Palar River sources. In addition, the Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB) supplies about 23.16 MLD from the Page 3 of 12 Chembarambakkam Lake source. Tambaram City Municipal Corporation also sources 15.20 MLD from its own standalone schemes drawing from the Palar River and 24.64 MLD from local sources such as hand pumps, open wells, and power pumps connected to HDPE tanks. Thus, the total water supply to Tambaram City Municipal Corporation from various sources amounts to approximately 73.00 MLD. Water is distributed through pipelines via overhead tanks to the concerned areas, while RO-treated water is also supplied to the public through private tanker lorries.
8. It is further stated in the report that, the TNPCB, vide letter dated 30.12.2024, requested the Commissioner, Tambaram City Municipal Corporation, to furnish an action taken report on the said incident. In response, the Commissioner reported that regular water quality testing and monitoring mechanisms are in place and clarified that the acute diarrhoeal outbreak was not due to water contamination, which was also confirmed by the post- mortem microbiological report. It is also stated that all necessary remedial and control measures have been taken, and preventive steps will continue to be implemented to avoid recurrence in the future.
9. Respondent No.2, the Central Pollution Control Board (CPCB), has filed its reply dated 07.04.2025, stating that an Action Taken Report (ATR) on the issue was sought from the TNPCB vide letter dated 20.12.2024. Pursuant thereto, the TNPCB submitted its report, the contents of which, as detailed above, are not reiterated herein to avoid repetition.
10. Respondent No.3, the Tamil Nadu Water Supply and Drainage (TWAD) Board, has filed its report dated 27.01.2025, stating that the TWAD Board supplies about 10.00 MLD of drinking water to the Tambaram City Municipal Corporation from Palar River sources, while the CMWSSB supplies 23.16 MLD from Chembarambakkam Lake. In addition, TCMC draws 15.20 MLD from its own standalone Palar River schemes and 24.64 MLD from local sources, totalling approximately 73.00 MLD. In Chengalpattu District, 12 Combined Water Supply Schemes are maintained by the TWAD Board, one of which is the Tambaram- Pallavaram Combined Water Supply Scheme serving Tambaram Page 4 of 12 City Municipal Corporation and seven other beneficiaries, including the Pallavaram Cantonment Board. The scheme sources water from infiltration wells, borewells, and an infiltration gallery in the Palar River at Melachery, Palayaseevaram, and Vengudi, Kancheepuram District. The water is conveyed through booster sumps and pumping stations at Deveriyambakkam, Oragadam, Krishnanagar, and Kadaperi to various distribution sumps of Tambaram City Municipal Corporation and other beneficiaries, ensuring proper chlorination before public distribution.
11. It is also stated that TWAD Board supplies about 30 lakh litres per day to three sumps of TCMC (Zone 2 - Pallavaram) located at Esa Pallavaram, Shanthi Colony, and New Colony, and about 4 lakh litres per day to two sumps of the Pallavaram Cantonment Board (Wards 6 and 7). TWAD's responsibility extends up to these sumps, from which the respective local bodies distribute the water after chlorination through their networks. Following reports of three deaths and hospitalization of 20 persons due to suspected contamination, a TWAD team comprising engineers and water quality analysts inspected the affected areas, collected water samples from relevant sumps, and sent them to the State-Level Water Quality Testing Laboratory, Chepauk, Chennai. Test results confirmed the absence of harmful microorganisms or sewage contamination. On 05.12.2024, TWAD technical staff and Tambaram City Municipal Corporation officials inspected the pipelines, sumps, and associated infrastructure and found no leakage or damage. As a precautionary measure, all sumps were cleaned, pipelines scoured, and chlorination wash carried out from 06.12.2024 to 08.12.2024 before resuming supply after testing. Continuous chlorination at prescribed levels was ensured, and daily sampling from 09.12.2024 to 12.12.2024 confirmed that residual chlorine levels were within safe limits.
12. It is further stated that TWAD Board operates 113 laboratories across the State, conducting approximately 8 lakh water quality tests annually. During 2024-25, 7.52 lakh samples were tested. In Tambaram City Municipal Corporation limits, water samples are collected and tested weekly to ensure potability, and Page 5 of 12 daily monitoring of residual chlorine levels is maintained by the Board's staff.
13. Respondent No.3, the Tamil Nadu Water Supply and Drainage (TWAD) Board, has filed yet another report dated 05.04.2025, detailing the existing and proposed water supply and underground sewerage infrastructure within the Tambaram City Municipal Corporation. It is stated in the report that Tambaram City Municipal Corporation, formed in September 2021 by merging several municipalities and town panchayats, covers 87.64 sq. km with a population of about 10.11 lakh and is divided into 5 zones with 70 wards. In Chengalpattu District, TWAD Board supplies 19.076 MLD of drinking water through 11 combined schemes and one dedicated scheme, benefitting over 7.8 lakh people, including residents of TCMC. Of the 70 wards in TCMC, 38 are fully covered by the Underground Sewerage System (UGSS), works are ongoing in 11 wards, and 21 wards remain to be covered. Completed UGSS projects include the Tambaram Municipality scheme under JNNURM (Rs.160.96 crore) with 178 km sewer lines and a 30 MLD STP, and the Pallavaram Municipality scheme (Rs.75.33 crore) with 159.74 km sewer lines, both implemented by the CMWSSB. The ongoing sewerage project under the Chennai Rivers Restoration Trust for Pammal and Anakaputhur, costing Rs.211.15 crore, includes sewer networks and a 27 MLD STP, and is expected to be completed by June 2025. For the remaining uncovered areas, a comprehensive Detailed Project Report worth Rs.3555.80 crore has been prepared through TNUIFSL, with Rs.750 crore sanctioned by the Government, proposing full UGSS coverage within three years of commencement. The Corporation submitted that, since plans are already in place for full implementation, no separate plan from TWAD is required as per the Tribunal's earlier direction.
14. Respondent No.4, the Ministry of Environment, Forests & Climate Change (MoEF&CC), has filed its reply dated 17.09.2025, stating that its primary role pertains to policy formulation for pollution abatement and environmental protection, which is implemented through the CPCB and respective SPCBs/PCCs under the provisions of the Environment (Protection) Page 6 of 12 Act, 1986, and the Water (Prevention and Control of Pollution) Act, 1974. It further submitted that, since water is a state subject, the responsibility for sewage collection, treatment, and disposal rests with the State Governments and local bodies, who are mandated to establish adequate Sewage Treatment Plants (STPs) to prevent contamination. The Ministry also clarified that the specific operational issues raised in the present case fall within the jurisdiction of the State authorities and do not directly come under the purview of the MoEF&CC.
15. Respondent No.6, the Tambaram City Municipal Corporation, has filed its report dated 05.04.2025, wherein it is stated that, on 04.12.2024 evening, a few residents of Tambaram City Municipal Corporation, Ward 13 (Kamaraj Nagar), and Pallavaram Cantonment Board, Ward 6, reported symptoms of vomiting and diarrhoea. Three deaths were reported between 04.12.2024 and 05.12.2024. Immediate visits were made by the senior officials from the Corporation and Cantonment Board to assess the situation and ensure adequate medical treatment. In the report, the death details of three persons were also reported. Autopsies conducted at the Government General Hospital, Tambaram, revealed no conclusive evidence of death due to waterborne infection. Samples of stomach contents, stool, and blood tested at the Institute of Microbiology, Madras Medical College, showed no pathogen growth. A total of 100 personnel, including five medical teams, nurses, sanitary and health inspectors, and support staff from Tambaram City Municipal Corporation and Pallavaram Cantonment Board, were deployed for emergency medical treatment and disease control in the affected localities, covering approximately 7,600 residents. On 05.12.2024, water samples were collected from Ward 13 (Tambaram) and Ward 6 (Pallavaram Cantonment Board), as well as from private tanker lorries supplying water to the area. Thirty special medical camps were conducted between 05.12.2024 and 10.12.2024. About 7,061 residents were provided with prophylactic medication and oral rehydration salts (ORS) through door-to-door distribution. Four engineering teams were mobilized to identify potential contamination sources in the water supply network.
Page 7 of 1216. The report further states that water supply was temporarily suspended as a precaution. All private water tankers supplying in the area were seized. Water supply was resumed only after adequate chlorination and testing. Overhead tanks and sumps were cleaned and disinfected between 05.12.2024 and 08.12.2024. Chlorination was ensured throughout the distribution system. Tests conducted by the Regional Water Analysis Laboratory (TWAD Board) on samples from Ward 13 (Tambaram) and Ward 6 (Pallavaram) showed no microbiological contamination. Routine water quality monitoring, including daily testing of residual chlorine up to the tail end of the distribution line, continues in Tambaram City Municipal Corporation.
17. It is further stated in the report that the Tambaram Corporation area, comprising the erstwhile municipalities of Tambaram, Pallavapuram, Pammal, Sembakkam, and Anakaputhur, along with adjoining Town Panchayats, has ongoing projects for underground sewerage systems (UGSS). Administrative sanction has been accorded for a Rs.1,240 crore UGSS project (Phase I - Rs.750 crore announced in the Budget). The Detailed Project Report (DPR) has been submitted for approval, and works will commence shortly. Based on the test results and post-mortem reports, the outbreak was not caused by water contamination. Nevertheless, all preventive and remedial measures have been undertaken, and continuous monitoring is being ensured to prevent recurrence.
18. Considered the pleadings, reports filed by the respondents and the submissions made by the learned counsels.
19. The matter before this Tribunal arises out of an unfortunate incident reported in December 2024, wherein three fatalities and several cases of diarrhoeal illness were suspected to have been caused by contaminated drinking water in the Tambaram locality. While the immediate cause of deaths could not be conclusively attributed to water contamination, the Tribunal's enquiry must focus beyond the immediate incident to examine systemic lapses in water supply, sewerage infrastructure, and municipal administration.
Page 8 of 1220. From the records and affidavits filed by the TWAD Board, it is seen that Tambaram City Municipal Corporation is a newly formed corporation created in September 2021 by amalgamating multiple municipalities and town panchayats. The population served is over 10.11 lakh, distributed across 70 wards in 5 zones. The rapid urban expansion of this corporation has not been matched by proportional development of underground sewerage and sanitation infrastructure. This mismatch between urban growth and civic infrastructure is a central issue in the case.
21. In terms of water supply, reports from TWAD, TNPCB, and Tambaram City Municipal Corporation consistently show that the total potable water supplied to the Tambaram area is approximately 73 MLD, sourced from multiple agencies--TWAD Board (19.076 MLD), CMWSSB (23.16 MLD), municipal Palar River schemes (15.20 MLD), and local sources such as open wells and ground water extraction (24.64 MLD). Chlorination, water testing, and supply protocols are stated to have been followed regularly, and laboratory test results from TWAD's State Water Quality Testing Laboratory have confirmed absence of microbiological contamination in the samples collected after the incident.
22. However, the issue cannot be viewed in isolation of water supply quality, as the real risk emerges from the absence of a fully functional Underground Sewerage System (UGSS) in the city. The TWAD Board report dated 05.04.2025 clearly states that only 38 out of 70 wards are covered with UGSS, 11 wards are under implementation, and 21 wards are not covered at all. In these uncovered areas, households depend on septic tanks, open drains, and in many cases, sewage flows into stormwater drains or natural canals. This creates a perennial risk of cross- contamination, particularly in areas where water distribution pipelines and sewer lines run adjacent or are inter-crossed in congested streets.
23. It is noteworthy that the completed UGSS projects in erstwhile Tambaram and Pallavaram Municipalities under the Jawaharlal Nehru National Urban Renewal Mission (JNNURM) are functional, and a 30 MLD sewage treatment plant (STP) in West Tambaram is operational. Similarly, Pallavaram sewage is treated Page 9 of 12 at the Perungudi STP. But these schemes cover only a part of today's enlarged Tambaram Corporation jurisdiction. Furthermore, the ongoing sewerage project under the Chennai Rivers Restoration Trust (CRRT), encompassing Pammal and Anakaputhur at a cost of Rs.211.15 crore and including a 27 MLD STP, remains incomplete. It was originally scheduled for completion by June 2025; however, the current status of the work has not yet been reported. The fact that significant portions of the city continue to function without underground sewerage is a serious public health concern. The Corporation itself has admitted this deficiency and submitted that a detailed project report (DPR) of Rs.3555.80 crore has been prepared to extend UGSS to all remaining wards, with Rs.750 crore already sanctioned, to be completed within three years of commencement.
24. The TNPCB and CPCB reports support the assertion that no immediate contamination of drinking water pipelines was detected, yet they also acknowledge that densely populated areas like Mariamman Koil Street, Kamaraj Nagar and Pallavaram Cantonment suffer from infrastructural deficiencies. These areas have narrow roads, ageing pipelines, unauthorized connections, and in certain parts, water pipelines run close to or over open drains. This proximity of water and sewage lines significantly heightens vulnerability to contamination after heavy rains, floods, cyclones, or pipeline damage.
25. Though laboratory reports and post-mortem findings did not conclusively establish that the deaths were caused by contaminated drinking water, it is equally true that a locality with incomplete sewerage coverage and intermittent pipeline maintenance remains perpetually at risk. The continued supply of water through public street taps in areas with open drains, informal sewage discharge, and limited chlorination monitoring is inherently unsafe and violates the right to clean drinking water.
26. Therefore, this Tribunal finds that the issue is not of an isolated contamination event but of systemic failure in planning and timely implementation of underground sewerage infrastructure. The evidence shows that the TWAD Board and Tambaram City Municipal Corporation acted swiftly after the Page 10 of 12 incident with chlorination, sump cleaning, medical camps, and supply suspension. However, these are remedial and reactionary measures, not long-term preventive reforms. The fact that Tambaram Corporation is partially dependent on ageing infrastructure inherited from its pre-merger municipalities has resulted in fragmented water management and insufficient sewage treatment capacity.
27. In the absence of confirmed water contamination, but recognizing existing systemic infrastructure gaps, this Original Application [O.A. No.29 of 2025 (SZ)] is disposed of with the following directions, subject to ongoing monitoring and periodic compliance review:
I. The TWAD Board and Tambaram City Municipal
Corporation shall:
a. Complete the ongoing Underground Sewerage System (UGSS) works in Pammal and Anakaputhur, which were originally scheduled for completion by June 2025; however, the current status of completion remains unreported, and the authorities are directed to furnish a detailed progress report immediately.
b. Commence execution of the Detailed Project Report (DPR) for the remaining 21 wards and complete the works as early as possible.
c. Submit quarterly progress reports to the TNPCB for monitoring till completion of the entire work.
II. The TNPCB shall conduct quarterly water quality audits and pipeline integrity inspections.
III. The State Government of Tamil Nadu shall ensure the timely release of sanctioned funds, prioritize the construction of UGSS and STPs under urban health and infrastructure planning initiatives, and continue to implement community health surveillance, Page 11 of 12 organize health camps, and conduct public awareness programs in vulnerable wards.
Sd/-
Smt. Justice Pushpa Sathyanarayana, JM Sd/-
Dr. Prashant Gargava, EM Internet - Yes/No All India NGT Reporter - Yes/No O.A. No.29/2025 (SZ) 07th November, 2025. Mn.
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