73% taps supplying raw, untreated water in West Bengal’s arsenic belt: CAG report

In the severely arsenic-affected districts of Nadia and North 24 Parganas, out of 63.15 lakh people provided with FHTCs through groundwater sources, 46 lakh people (73 per cent) receive water without treatment through arsenic-iron removal plants (AIRP).

A similar deficit exists in Birbhum district, a major fluoride belt, where out of 4.61 lakh fluoride-affected households, only 1.48 lakh (32 per cent) receive treated piped water. Nearly two-thirds of the targeted population in Birbhum remains dependent on unmonitored or contaminated supplies.

Public health risks ignored

“Providing tap infrastructure without mandatory chemical treatment plants in known contamination zones undermines the core objective of safe drinking water delivery, posing long-term public health risks,” read excerpts from the CAG performance audit report.

Experts point out that prolonged exposure to inorganic arsenic in drinking water is linked to chronic skin lesions (hyperpigmentation and keratosis), peripheral vascular diseases like blackfoot disease, and elevated risks of skin, bladder, kidney, and lung cancers. High fluoride intake, on the other hand, causes debilitating dental and skeletal fluorosis.

The CAG report stressed that while pipe-laying and tap coverage metrics have expanded rapidly, the delay in integrating dedicated treatment plants (AIRPs and fluoride demineralisation units) compromises public safety in vulnerable rural belts. The auditor urged the PHED to streamline installation timelines so that pipeline expansion aligns with water safety treatment.

History of waterborne disease outbreaks

The absence of routine filtration, chlorination, and functional treatment units also allows microbial contamination to enter piped supplies, particularly during monsoon floods and waterlogging.

Recent real-world outbreaks across the state follow the exact pattern highlighted by the CAG audit. In New Town, North 24 Parganas, an outbreak of Typhoid fever and Hepatitis A struck a private housing complex, affecting over 50 residents across dozens of families and resulting in multiple hospitalisations. Investigations revealed that sewage and canal water had infiltrated primary supply lines, compounded by the absence of filtered municipal water in the area.

Similarly, in the Panihati municipal area near Kolkata, a severe waterborne diarrhoea outbreak affected over 300 residents and caused two deaths when old underground drinking water pipelines running parallel to open municipal drains cracked, drawing raw sewage straight into home kitchens. In May 2021, the neighbouring Howrah Municipal Corporation area saw over 150 people hospitalised with acute diarrhoea over a single weekend due to similar cross-contamination.

The CAG report emphasised that laying taps and underground pipes without integrating functional filtration or chlorination units creates a direct conduit for pathogens. Because families often assume tap water is safe and drink it without boiling, a single pipe fracture can transform a localised leak into a widespread health emergency within 24 to 48 hours.