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Observations based on the National Water Quality Monitoring Programme (NWMP) data for 2022, 2023, and 2024 (January to August) indicate significant faecal contamination in the Periyar river, Kerala State Pollution Control Board (KSPCB) told the National Green Tribunal (NGT) in a report on November 19, 2024 .
The contamination indicates pollution from urban and domestic sources, the report said. A concerning trend of low dissolved oxygen (DO) levels has been observed in the river, particularly in the lower stretches during the summer months.
The KSPCB also told the NGT about a fish kill incident that occurred between May 20-21, 2024. The High Court of Kerala, in its order dated June 10, 2024, directed the formation of a committee to suggest measures to curb pollution in the river. An interim report was filed before the High Court on July 3, 2024.
On May 20, 2024, three shutters of the Pathalam regulator-cum-bridge were opened by the state government’s irrigation department. The released water, containing high organic loads and very low DO levels, combined with anaerobic sludge settled upstream of the bund, flowed downstream. The situation was exacerbated by high tide conditions on the downstream side, which occurred within hours of the shutters being opened.
Reports from the KSPCB over recent years have highlighted similar water quality issues related to the Pathalam regulator. During the summer months, when the bund remains closed for extended periods, organic waste from residential and commercial areas accumulates in the riverbed upstream of the bund. This accumulation contributes to a severe drop in DO levels when the bund is eventually opened.
The fish mortality in May 2024 was attributed to the sudden, sustained flow of DO-depleted water and organic sludge downstream, causing a sharp drop in DO levels below the bund.
Data from April 1 to May 31, 2024 show that DO levels at the Pathalam bund were critically low, even dropping to zero on some days. This was likely due to untreated wastewater or sewage being discharged into the Periyar river. However, the DO levels downstream of the bund improved from May 23, 2024, rising above 4 milligrammes per litre, which is essential for aquatic life.
There are 43 effluent-generating industries in the Eloor-Edayar industrial area, all operating with the consent of the KSPCB. Of these, only five industries are permitted to discharge treated effluents of specified quality into the Periyar river. The remaining industries treat their effluents and either reuse them or dispose of them through soak pits.
Most of the catchment area of Chandlai Lake in Jaipur district is surrounded by residential areas and textile industries located in the Sanganer area. The lake receives domestic and industrial wastewater throughout the year, discharged primarily by these textile units the joint committee told the NGT in a report filed November 21, 2024.
Although Chandlai lake in Jaipur district is not a notified wetland, it has been proposed as a Ramsar site by the state government and is awaiting finalisation. In contrast, the Chandlai lake located in Tonk district has been officially declared a notified wetland by the Rajasthan government.
During an inspection, the committee observed encroachments in the catchment area of the Chandlai dam and directed the water resources department to submit a detailed report on identified encroachments and the actions taken. Two main canals lead to Chandlai lake — one originating from the Gular dam and the other from the Ramchandrapura dam, both situated along the Dravyavati river.
Stormwater, treated wastewater from sewage treatment plants (STP) and effluents from textile clusters flow into the Dravyavati river, eventually reaching Chandlai lake. The Dravyavati river project operates five STP with a cumulative treatment capacity of 170 million litres per day (MLD).
The textile industries in and around the Sanganer area primarily engage in textile processing and are clustered in non-confirming zones. A significant number of these industries discharge untreated wastewater into the Dravyavati river and connected canals.
The joint committee collected four surface water and groundwater samples, and the analysis confirmed that water flowing into Chandlai lake is heavily polluted. According to the most recent survey, approximately 1,255 textile units are established in the Sanganer area.
These industries are operating without the requisite permissions from local bodies, the Revenue Department, or the Rajasthan State Pollution Control Board (SPCB). On September 9, 2024, the SPCB issued final show-cause notices to 1,163 operational textile units in Sanganer for violating provisions of the Air (Prevention and Control of Pollution) Act, 1981 and the Water (Prevention and Control of Pollution) Act, 1974. Legal action and closure orders are underway against these units.
Additionally, the SPCB has issued closure orders to 29 illegally operating textile units found to be directly discharging wastewater into drains leading to Chandlai lake. These units cannot be connected to the Common Effluent Treatment Plant pipeline network.