Data is misleading and underestimates pollution, allege scientists
The Central Water Commission has compiled and averaged a decade (2001-2011) of water quality data, collected from 371 monitoring stations located at all major, medium and minor rivers in India. The report, made available recently, but published in August this year, has identified hot spots or stretches of rivers where certain water quality parameters have been found to exceed permissible limits (see map).
The report classified the river stretches as per the Central Pollution Control Board’s (CPCB) criteria, and ascertained whether it was fit for bathing. According to the data, 17 monitoring stations were found to have dissolved oxygen levels below what is considered fit for bathing. The biochemical oxygen demand (BOD), an indicator of oxygen depletion in a water body, too, was found beyond limits in 37 of the 371 water quality stations.
Authorities have been unable to reduce the gap between sewage generated and treatment infrastructure. But the Centre has often backed up its river pollution abatement efforts and programs. Jayanthi Natarajan, Union environment minister on November 28 claimed in the Lok Sabha that organic pollution loads have reduced in river stretches. Yet as per CPCB data, less than a third of the estimated 38,254 million litres of sewage generated each day in Class I & Class II towns of the country is currently being treated; additional sewage treatment capacity for 26,467 million litres per day needs to be created to bridge the gap. Abstraction of water for irrigation, drinking, industrial use and power compounds the challenge, leaving lesser freshwater for dilution of rivers.
|River water quality classification|
oxygen demand (mg/l)
(most probable number/100ml)
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