In 1892, bacteriologist Ernest Hanbury Hankin arrived in Agra to take up the role of Chemical Examiner, Government Analyst, and Bacteriologist for the British Government's United Provinces, Punjab, and Central Provinces. His principal responsibility was to safeguard British troops from deadly illnesses, particularly the much-feared cholera.
To his great surprise, he saw that every morning, thousands of people were washing themselves, their animals, and their clothing in the unclean, cloudy waters of the Yamuna River. Typical of the colonial official, he believed the water was "quite dangerous for consumption" and that Hindus' "veneration of these hallowed rivers demonstrated their lack of understanding of health and hygiene”.
A rude shock awaited him around the next corner. Just two years later, in February 1894, Allahabad hosted the Maagh Mela. Millions arrived for the holy dip and camped along the riverbank in Prayag. With half-burned bodies frequently making their last voyage in the river and millions bathing on the ghats, Hankin was sure that a huge cholera outbreak was on the way. His other colonial authorities believed the Ganges to be the primary channel for the propagation of the cholera epidemic.
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Cholera did occasionally break out at a pilgrimage site, and because it is a waterborne disease, Hankin anticipated that the epidemic would spread to settlements farther downstream. To his amazement, cholera spread only when an infected pilgrim brought the illness back; otherwise, the villages downstream remained spared of the epidemic. He wondered, “How is this possible, given that cholera is transmitted by water? Can we presume that the river water does not carry the cholera germ?”
The curios case of Ganga
After studying medicine at the prestigious St Bartholomew's Hospital Medical School, he developed an interest in bacteriology and worked with Robert Koch in Berlin and Louis Pasteur in Paris before moving to India. His passion was in bacteriology.
Within the first two years of his visit, he noted that the native communities around the Ganges and Yamuna rivers were never afflicted with cholera by drinking water from them, despite cholera bacteria being regularly brought into these rivers by sewage. He was intrigued by the fact that not only were the waters of the Yamuna and Ganga drinkable, but they did not putrefy even when all of the settlements along the banks dumped their waste into the river. In contrast, all the major European rivers stank of human sewage and industrial pollution.
He was amazed that despite the pollution from huge towns and the habit of discarding half-burnt bodies into rivers, microorganisms and organic stuff could not live long in these river waters. While pandits and local hakims happily attributed it to the supernatural qualities of the holy Ganga, Hankin sought a scientific answer. Fazed by the riddle, he did what any reasonable scientist would do. He began a programme to carefully assess the water quality of the Ganga and Yamuna.
He gathered samples from Agra's sewers and discovered Vibrio cholerae, the cholera-causing bacteria. He also gathered samples from the river and wells along the banks and recorded which had cholera bacteria and which did not. However, even samples retrieved from the Yamuna and Ganga, a bit further away from the sewage outflow, were devoid of Vibrio cholerae bacteria, but water samples from the wells were teeming with them. He was astonished. He realised that some mechanism in the Ganga and Yamuna rivers prevented cholera germs from surviving.
When he tested with the samples, intentionally introducing the cholera pathogen, he discovered, to his astonishment, that ‘water of the Ganges kills the cholera germ in less than three hours’. He repeated the experiment, first filtering and then boiling the Ganges water. The filtered water still effectively killed the bacteria, but the germs in the boiled water survived and proliferated. Thus, he discovered that boiling weakened the Ganges water's potential to kill germs, but filtered and fresh water from the Ganges and Yamuna inhibited pathogen growth. He also found that, besides cholera, the Ganga and Yamuna rivers could restrict the growth of typhoid bacteria.
He concluded, "I have not yet discovered the nature and origin of the antiseptic substance present in the waters of the Ganges and Jamuna rivers, what appears interesting is that they explain why cholera does not travel downstream rivers in India."
Following these findings, Hankin advocated using river water rather than well water at Hindu pilgrimages such as the Kumbh Mela.
The legend
From the sixth century BCE, the Ganga-Yamuna Doab area emerged as a new cultural zone and political hub for various imperial dynasties, including the Mauryans, Guptas, Delhi sultans, and the Moghuls. These dynasties were connected with the Ganges valley, and political and commercial life revolved around the river. The river and its banks supported a large population, and its cultural significance cannot be overstated. Legends arose glorifying the heavenly attributes of the Ganga and its jal, underscoring its role in the lives of millions.
The sacred waters of the Ganges, known as Gangajal, are deeply revered in Indian culture. The Mahabharata states, "As amrita is to the gods, so Ganga water is to human beings." This profound comparison underscores the spiritual importance of the Ganges. According to Skanda Purāna's Gangasahasranaam, "the medicated water of the Ganga, in sweetness, lightness and taste, has no equal, and that the water of this river, howsoever kept long, does not stink or spoil." This cultural reverence for the Ganges is a testament to its unique properties and the role it plays in the lives of millions.
The Mughals felt enchanted by the ordinary people's veneration for the Ganga. Akbar created a new city near Prayag called Ilāh bās, the Abode of Gods, which the British misunderstood and corrupted as 'Allahabad'. Dr Ram Nath's book Private Lives of the Mughals states that Akbar stationed a trustworthy person at Ganga's banks to despatch Gangajal in sealed jars every day for drinking and cooking. Abul Fazl, a 16th-century chronicler, records Akbar's habits and says, "His Majesty calls this source of life the water of immortality... Both at home and on his travels, he drinks Ganges water. Trustworthy persons stationed on the banks of the river dispatch the water in sealed jars.... Now that his majesty is in the Punjab, water is brought from Hardwar."
The Ganga as it flows in Varanasi.
Hankin's conclusion that a mysterious, undiscovered form of life killed the pathogens and purified the Gangajal was published in the Annals of Pasteur Institute in 1896. This was first disregarded as folklore but later validated by several scientific studies. The Ganges somehow manage to cleanse itself. Hankin's discovery of antibacterial characteristics further reinforced the beliefs in the magical quality of the Gangajal, giving rise to the concept of Ganga's mystical 'self-purifying' potential.
What is the self-purification ability?
An old Slovenian saying encapsulates the heart of rivers' self-purification ability: “the water is cleansed when it runs over seven stones”. A complicated natural process comprising physical, chemical, and biological forces interweaves and purifies the contaminated river after a given amount of time.
Dilution is one of the primary purifying processes. When wastewater is released into a fast-flowing and turbulent watercourse, the ratio of stream discharge to pollution discharge increases, effectively purifying the water. Similarly, the hyporheic zone of a riverbed, consisting of gravel and sand, functions as a sieve, sifting minute particles of organic waste or inorganic material and successfully attaching them to the clay in the riverbed, eliminating contaminants in the flowing water.
Domestic sewage, including organic contaminants, is a major pollutant that reaches waterways. These are frequently hydrolysed, which means they are chemically broken down by an interaction with water, converting and destroying the contaminants. Photolysis is a method that uses light to break down some contaminants. Chemical processes are frequently linked to physical processes; hence, they are referred to as “physical-chemical processes”.
Although physical-chemical processes contribute to purification, biological activities are critical to river water's self-purification ability, which relies heavily on the population of organisms that dwell there. Decomposers are microbes that operate directly to degrade and decompose contaminants into basic components and mineral compounds, a process known as mineralisation. Animals and plants then ingest these degraded minerals as nourishment and incorporate them into their bodies. A complex interaction of many life forms aids in the conversion of polluting organic wastes in rivers into nutrients for the ecosystem of species that dwell there.
Ganga’s secret: A tiny virus and the mighty Himalayas
But what is the secret of the Ganga's self-cleansing properties? It took several years until Frederick W. Twort and Félix d'Hérelle identified a new kind of virus, known as bacteriophages or bacteria eater. Subsequent research revealed that the Ganges contained more of these bacteriophages, natural bacterial predators. Just as viral infections, such as COVID-19, may be fatal to humans, infected bacteria commonly die. Thousands of bacteriophage species have been discovered in the Ganges, which helps to keep bacterial growth in check. Ganges' unique biological defence mechanism contributes significantly to its purifying ability.
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Interestingly, a recent study discovered the existence of bacteriophages against harmful bacteria in the Ganges waters, even near its source at Gomukh. Meltwater streaming from the Himalayan permafrost carried phages that killed Escherichia bacterium species, including pathogenic E. Coli. The researchers hypothesise that these bacteriophage viruses were locked in the Himalayan permafrost as abiotic particles millions of years ago and that when the glaciers thaw, they get activated in the meltwater.
The discovery of bacteriophages and bacterium predators helped to unravel some of the enigma. However, this alone cannot explain the Ganges' ability to purify itself. The second mechanism was discovered on the slopes of the mighty Himalayas.
The Himalayas are the world's highest, youngest, and most active continental mountain system. They were formed just 50 million years ago and continue evolving, rising by about 1 cm yearly. Rainwater often contains dissolved carbon dioxide (CO2), making it somewhat acidic. When this mildly acidic rain falls on the young Himalayan calcium-bearing silicate rocks, a chemical reaction occurs, forming limestone and leaching of silicate and other ionic minerals.
Because the Himalayas are young and constantly rising, new rock surfaces are exposed, resulting in significant rates of silicate leaching and chemical denudation. For example, the Ganga depletes almost 72 tonnes per km per year, nearly two to two and a half times the global average. The Ganga-Brahmaputra river system carries around 130 million tonnes of dissolved salts to the Bay of Bengal, accounting for almost 3% of the total world river flux to the oceans.
The silicates and metallic ions dissolve in runoff water and enter streams and rivulets that flow into the Ganges, where they are carried downstream. The transported silicates settle and adhere to the clay at the river's bottom, and the leached metallic minerals become entrenched in the riverbed clay.
River water is a chemical soup of dissolved minerals constantly subjected to complicated physicochemical and biological processes. Metal ions in this soup inhibit the growth of bacteria by adhering to their surfaces and limiting pathogen proliferation. This is also a crucial mechanism for purifying Ganges river water.
Limits to self-cleansing
As with all natural processes, there is a limit beyond which the natural mechanism falters. Self-purification can only be effective if the volume of wastewater does not exceed a river's natural ability to clean itself. The two chief reasons for their incapacity to clean themselves are human-made synthetic pollutants and sewage, which far exceeds the self-purification capability of natural systems.
The river's flow allows oxygen from the atmosphere to dissolve in the river ecosystems. Aquatic vegetation and plankton, a type of microbe, create food through photosynthesis, releasing oxygen, some of which dissolve and refill the oxygen supply for the intricate web of aquatic life. Adequate dissolved oxygen in the river water is required for complete purification, meaning all organic stuff is degraded and mineralised.
When there is a dearth of dissolved oxygen, the system becomes choked. The decomposers are unable to metabolise dead materials, and mineralisation is incomplete, resulting in a shortage of nutrients for growth. Poor vegetation growth further reduces the levels of dissolved oxygen. Further, partially decomposed organic molecules breakdown into methane and hydrogen sulphide, which have a galling stench. The river gradually deteriorated and became unable to rejuvenate itself.
Ganges in trouble
Two processes undermine and restrict Ganga's potential to renew. When the tributaries converge to create the Ganga, they transport dissolved silicate. However, sewage and industrial contaminants in the upper reaches bind to these silicates and metallic ions, leaving nothing when the river reaches its mid-course. By the time Ganga reaches Gomti, the silicate concentration has decreased. This diminishes the availability of metallic ions in Ganga, which is needed to suppress pathogen populations.
Various investigations have revealed an abundance of bacteriophages. Ironically, it is not a source of pride that bacteriophages exist in higher numbers because this suggests that their prey, bacteria, is abundant. Simply put, a higher number of bacteria-killing viruses implies bacterial infection. Organic sewage stimulates the growth of bacteria, overwhelming the bacteriophage. Hence, larger quantities of bacteriophages do not indicate the river's vitality or virility but rather its death and decay.
Alarmingly, research released in June 2020 on the numerous and broad range of phages discovered antibiotic resistance genes in India's Ganga River. This highlights the massive public health concern looming over the Gangetic plains and warns that the health of Ganga is deteriorating.
Earlier studies
Ganga is admired as India's holy river, and bathing in it is considered a source of salvation; hence, pilgrims assemble for a dip at several points throughout Ganga's course and during the Kumbh or Maha-Kumbh festival. The large crowds at the Kumbh just exacerbate the problem.
During the previous Kumbh, scientific studies were conducted to assess the impact of mass bathing. For example, a study led by Sanjay Dwivedi of the CSIR-National Botanical Research Institute examined changes in physicochemical properties, microbial diversity, and the role of bacteriophages in controlling the bacterial population of Ganga water during mass ritualistic bathing during the 2013 Maha-Kumbh festival. The Maha-Kumbh saw a significant rise in biological oxygen demand (BOD), chemical oxygen demand (COD), hardness, total dissolved solids (TDS), and ion levels. In contrast, dissolved oxygen levels in Ganga waters decreased.
BOD measures the quantity of oxygen microorganisms utilise when breaking down organic materials in water over time. It indicates the level of organic pollution in water and points to untreated sewage discharges. COD measures the amount of oxygen utilised to chemically oxidise organic and inorganic molecules, and it is widely used to analyse industrial pollution. Less dissolved oxygen harms the fish and other animals that reside in the river. The authors concluded that the increased pollution load exceeded its self-cleaning characteristics.
After evaluating data from the 2019 Kumbh Mela, the Central Pollution Control Board published a paper titled 'Environmental Footprints of Mass Bathing on Water Quality of River Ganga during Kumbh Mela'. The analysis indicated that at various ghats during the Kumbh Mela, levels of Biological Oxygen Demand (BOD) and faecal coliform in the Ganga River surpassed tolerable limits, indicating severe water pollution from mass bathing. With an estimated 13.02 crore people participating, the strain on the Ganges was substantially higher; imagine what it will be like when the number of participants increases dramatically this time?
Anviksiki
For many believers, taking a dip in the Ganga during the Kumbh is a matter of faith. Examining the pollution levels in the Ganges is not an affront to their religious belief but rather a concern for their safety and the river's well-being. Closing our eyes to the realities of contamination will not make it go away.
Unfortunately, in recent months, any mention of pollution related to the Mahakumbh has sparked fierce discord and vexing competitive victimhood; why only us? They also clean their face and legs in a community pool before praying. Then comes a scientist, brandishing publications and saying that the Ganga has self-purifying properties, certifying it as the world's cleanest river. Accusations are traded, tempers boil, and reason takes a backseat.
Kautilya says in Arthasastra-
pradīpaḥ sarvavidyānāmupāyaḥ sarvakarmaṇām |
āśrayaḥ sarvadharmāṇāṃ śaśvadānvīkṣikī matā ||
The study of critical inquiry is always considered a lamp for all branches of knowledge, a means in all activities, and a support for all religious and social duty.
Further he adds,
dharmādharmau trayyāmarthānarthau vārttāyāṃ nayānayau daṇḍanītyāṃ balābale ca etāsāṃ hetubhiranvīkṣamāṇā lokasya upakaroti vyasane'bhyudaye ca buddhimavasthāpayati prajñāvākyakriyāvaiśāradyaṃ ca karoti
Investigating by means of reasons, good and evil in the Vedic religion, profit and loss in the field of trade and agriculture, and prudent and imprudent policy in political administration, as well as their relative strengths and weaknesses, the study of critical inquiry (anviksiki) confers benefit on people, keeps their minds steady in adversity and in prosperity, and produces adeptness of understanding, speech and action.
Flagging the worrisome pollution levels does not restrict believers' right to fulfil religious duties or take a pilgrimage. If we want to commemorate Ganga and the piety of millions, we must prioritise critical inquiry, anviksiki, as advocated by Kautilya, and find ways to arrest the deterioration of the river ecosystem.
During this Kumbh, the Central Pollution Control Board (CPCB) gathered samples and revealed frightening results. Let us focus on one aspect — Faecal coliform levels. Coliforms are bacteria found in warm-blooded animals' intestines, including humans. Faecal coliform bacteria are associated with human or animal waste. Elevated levels of faecal coliform are a symptom of sewage pollution. The permissible limit of faecal coliform in bath water is 2,500 units per 100 mL, while the desirable level is 500 MPN/100 mL. However, according to CPCB records (http://103.7.181.103:4000/), values were exceeded on several occasions and in multiple locations, reaching frightening levels as high as 23000, 30000, and even 50,000.
This plainly shows that the human sewage disposal from the mass gathering contaminated the river, and whatever process was put in place to purify the human excreta before dumping it into the river did not succeed. A systematic analysis of pollutant profiles, identifying the sources of contamination, and devising a strategy to stop them necessitates reasonable and scientific investigation.
