The pollution crisis in the Sirsa river likely has its roots in a massive gap in the treatment of industrial effluent and domestic sewage generated in and around Baddi town of Himachal Pradesh. It was having serious implications for the Sutlej into which the Sirsa river eventually flows.
As per the letter written by Ropar AAP MLA Dinesh Chadha to Secretary environment Ropar a copy — of which was available with The Tribune — nearly 2,200 industries were operating in Baddi area of Himachal Pradesh.
Out of these, 1,000 generate liquid waste, but wastewater from only about 377 units is reportedly reaching Common Effluent Treatment Plant (CETP) in Baddi. The remaining effluent is alleged to be finding its way into drains and watercourses, ultimately reaching the Sirsa and then the Sutlej, Chadha has alleged.
The MLA has also stated that Baddi has an officially recorded population of about 2.2 lakh, while the actual population is estimated to be around four lakh because of the large migrant and industrial workforce.
Even for the officially recorded population, the sewage treatment requirement is estimated at around 32 MLD (million litres per day), against which only a 5 MLD sewage treatment plant is presently operational. The untreated sewage is allegedly flowing through drains, including the Chamoli drain, into the Sirsa, the MLA has stated in his letter.
Chadha — when asked about the sources of his data — said that he has collected it from the official sites of Himachal Pradesh Pollution Control Board and from the officials of Himachal.
PPCB sampling between July 2025 and March 2026 illustrated that the Sirsa had deteriorated sharply by the time it reached Ghanauli in Ropar district. In March 2026, total coliform reached 60,000 MPN (Most Probable Numbers)/100 ml, while faecal coliform touched 17,000 MPN/100 ml.
The figures are particularly alarming when compared with the Central Pollution Control Board (CPCB) criteria. For Class B water meant for organised outdoor bathing, total coliform should not exceed 500 MPN/100 ml, while the desirable limit for faecal coliform is 500 MPN/100 ml and the maximum permissible level is 2,500 MPN/100 ml. Thus, the faecal-coliform level recorded at Ghanauli was 34 times the desirable limit.
The river’s biochemical oxygen demand (BOD) has also remained above the prescribed level. In December 2025, BOD shot up to 15 mg/L, against the CPCB Class B limit of 3 mg/L. It subsequently stood at 4 mg/L in January, 6 mg/L in February and 4.8 mg/L in March.
Earlier, CPCB assessments of the Baddi-Nalagarh industrial belt documented substantial pollution loads in drains feeding the Sirsa. One CPCB document recorded BOD levels of 56 mg/L in Sandholi Nallah, 30 mg/L in Housing Board Nallah and 200-230 mg/L in the HPSIDC drain, besides a CETP outfall carrying a flow of 17.5 MLD with BOD of 22 mg/L, the MLA has stated in his letter.
Official environmental records have also identified untreated sewage generated in the Baddi-Barotiwala-Nalagarh area as a major source contributing to pollution in the Sirsa.
The river ultimately merges with the Sutlej near Ropar. Recent inspections have already found industrial waste and other pollutants accumulating at the Ropar Headworks. PPCB has sought a joint investigation with pollution-control authorities of Himachal Pradesh and Haryana.
