Faith vs science: Why Ganga is considered 'self-cleaning', scientists cite bacteriophages as ‘natural purifiers’

A debate over blind faith and health concerns has erupted after a Central Pollution Control Board (CPCB) report detected alarming levels of faecal coliform bacteria in the Ganga at Prayagraj. The revelation comes at a crucial time — during the Maha Kumbh festivities, where over 50 crore devotees have taken a holy dip in the river.  

Faecal coliform bacteria are found in the intestines of warm-blooded animals and humans. Their presence in water often indicates contamination, potentially carrying harmful pathogens like viruses and parasites that originate from excreted faecal matter.   

Case for Ganga’s ‘self-purification’  

Amid concerns over water quality, a recent study suggests that bacteriophages — viruses that selectively destroy bacteria — play a crucial role in naturally purifying the Ganga. Researcher Dr Ajay Sonkar, who conducted the study, described these bacteriophages as “security guards” that target and eliminate harmful bacteria introduced by millions of bathers at the Maha Kumbh.  

Bacteriophages, unlike chemical treatments, are highly specific and attack only harmful bacteria without disturbing beneficial microbial communities. They are known to combat antibiotic-resistant bacteria and are even being explored for medical advancements, particularly in phage therapy as an alternative to antibiotics.  

Legacy of scientific inquiry  

The mystery of Ganga’s antibacterial properties dates back to 1891, when British bacteriologist Ernest Hankin noticed something unusual while studying cholera outbreaks along the riverbanks. Despite the dumping of bodies and sewage, cholera outbreaks did not spread as aggressively as expected. He hypothesized that an unknown agent in the water was killing the bacteria before they could cause widespread infection.  

It wasn’t until 1917 that French scientist Félix d'Hérelle identified this agent as bacteriophages. Now recognized as the father of bacteriophage therapy, d’Hérelle’s work confirmed that these viruses were responsible for the Ganga’s ability to neutralize harmful bacteria.  

Pollution vs Purification  

Despite its historical reputation for self-purification, the Ganga is heavily polluted by industrial waste, untreated sewage, and chemical effluents. Scientists acknowledge that bacteriophages may help control bacterial contamination, but their effectiveness against large-scale pollution remains debated.  

With the CPCB raising alarms over faecal contamination, the debate between faith and science continues. Is the Ganga truly self-purifying, or is pollution overwhelming its natural defenses?