#6: Why 70% of Urban Sewage Goes Untreated in INDIA?
Over 72% of urban wastewater in India is released into the environment without any processing.
India’s cities generate an enormous volume of sewage every day, yet most of it is never treated.
Over 72% of urban wastewater in India is released into the environment without any processing. In 2020-21, urban areas produced about 72,368 million litres of sewage per day but had a treatment capacity of only 31,841 MLD (million litres a day).
That installed capacity amounts to roughly 44% of the sewage generated.
The reality is even worse: many treatment plants don’t operate at full capacity due to poor maintenance and other issues.
As a result, only 28% of the sewage was actually being treated, meaning that the remaining 72% – nearly three-quarters – flowed untreated into rivers, lakes, and the soil.
India dumps enough raw sewage daily to fill 18,000 Olympic-sized swimming pools straight into the environment.
This is an appalling failure of basic public infrastructure, and it has persisted for decades despite India’s rapid growth and modern ambitions.
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The consequences of this neglect are dire.
Untreated sewage is the single most significant source of water pollution in the country. It turns urban rivers into foul, toxic streams.
The Yamuna River in Delhi, for instance, has become one of the most polluted in India due to the capital’s endless discharge of waste.
Nationwide, the Central Pollution Control Board (CPCB) has identified 351 contaminated river stretches across 323 rivers, mainly because of high biochemical oxygen demand from sewage dumping.
In effect, much of India’s freshwater is sullied by the very cities it sustains.
Some of the studies (links below) have estimated that up to 75-80% of India’s surface water may be polluted in large part due to sewage release.
Lakes and wetlands near cities meet the same fate – frothing with sewage and industrial effluents, devoid of oxygen, and often reeking of decay. Aquatic ecosystems are collapsing in these areas as fish and other organisms cannot survive the high pollution load.
Groundwater is at risk too: in many unsewered towns, excreta seeps from pit latrines and drains into the soil, contaminating wells and boreholes.
The environmental damage from unchecked urban sewage is not a distant, abstract issue – it is unfolding in plain sight as rivers turn black and frothy downstream of every major city.
This is not just an environmental crisis but a public health catastrophe.
Millions of Indians are exposed to water contaminated by faecal matter. Pathogens from sewage find their way into drinking water sources and the food chain. Water-borne diseases like diarrhoea, cholera, typhoid, and hepatitis are widespread as a result.
Every year, an estimated 37.7 million Indians suffer from water-borne illnesses.
Children are the worst affected – in 2015 alone, over 1,17,000 Indian children under five died from diarrheal diseases caused by polluted water.
That is a staggering death toll directly tied to poor sanitation and sewage management. Repeated bouts of diarrhoea and other infections also leave many more children malnourished and vulnerable, perpetuating a cycle of poverty and ill health.
The economic costs pile up in hospital bills, lost productivity, and stunted human potential. According to UNICEF, water-borne diseases impose a financial burden of around $600 million per year in India. Communities living in low-income urban areas face the harshest impacts.
Poor neighbourhoods often lack piped safe water and depend on lakes or borewells that are easily contaminated by nearby sewage drains. These residents, who can least afford it, end up paying with their health.
Inequality is literally embodied in who gets to drink clean water; the wealthy can buy bottled water and filters, while the poor suffer cholera outbreaks from the filthy river flowing past their slum. It is a grave injustice that the lack of sewage treatment in our cities hits the most vulnerable the hardest.
How did we end up in this situation where 70% of urban sewage goes untreated?
The core reason is that urban development in India has been profoundly uneven and shortsighted when it comes to sanitation infrastructure.
City populations exploded, but sewer networks and treatment plants did not keep pace. Basic sanitation was not prioritized for decades.
Even today, in many cities, only a fraction of households are connected to a sewer line.
As of the 2010s, only about one-third of urban Indian households with sanitation had toilets linked to underground sewers (link below).
The rest use septic tanks and rudimentary pits or simply flush waste into open drains. That means huge volumes of sewage never even reach a treatment plant.
Sludge from septic tanks is often dumped illegally into watercourses or open land because proper faecal sludge management is absent in most areas. Stormwater drains meant for rain frequently carry raw sewage into our cities because there is nowhere else for it to go.
This lack of infrastructure is especially glaring in smaller cities and towns. Metropolitan areas like Delhi or Mumbai at least have some treatment facilities (though still inadequate). Still, many mid-sized cities and most small towns have zero sewage treatment capacity.
For example, states in the Northeast had almost no functional sewage plants as of 2020.
Even a large state like Bihar, generating over 2,200 MLD of sewage, had only a 10 MLD plant in place.
Essentially, vast stretches of urban India never built the pipes and plants needed to safely handle human waste.
This is a colossal failure of planning and governance that has spanned decades.
Where infrastructure does exist, operational failures compound the problem.
It’s common to find expensive sewage treatment plants (STPs) running below capacity or even lying idle.
Reasons range from broken equipment, erratic power supply, and poor maintenance to not having sewage pipelines feeding the plant.
In some cities, treatment plants sit ready. Still, the sewer network doesn’t adequately carry waste, an absurd situation resulting from fragmented planning.
Workforce and technical expertise are also lacking; many local bodies do not have enough skilled engineers and workers to manage the plants.
Meanwhile, effluent standards are often flouted – even the sewage that does get “treated” is sometimes only partially treated.
Government audits have found a significant number of plants discharging effluent that fails to meet environmental norms.
In short, not only do we have too few plants, we’re not even fully utilizing the ones we have – and those that do run sometimes aren’t doing a good enough job.
This double failure means raw or poorly treated sewage continues to course into waterways right under the noses of regulators.
A chronic lack of political will and accountable governance on urban sanitation is at the heart of the issue.
Water and sanitation are state subjects in India, so city governments and state authorities carry the primary responsibility. However, sewage systems are costly and largely invisible to the public until a crisis hits.
Politicians have historically found it more rewarding to cut ribbons on new flyovers or metros than on sewage plants.
Local municipal bodies, which are often cash-strapped and stretched thin, put whatever funds they have into garbage collection or road repair, not underground drains.
The result is that cities kept expanding without laying the invisible pipes for waste.
When the pollution became impossible to ignore, state agencies and the central government stepped in with sporadic schemes rather than sustained policy.
There is also fragmentation of responsibility – different agencies handle water supply, sewage, storm drains, and environmental regulation, with poor coordination among them.
So when a river turns into a sewer, everyone and no one is to blame.
Environmental laws exist on paper.
The Water (Prevention & Control of Pollution) Act of 1974 and Environment Protection Act of 1986 require local bodies and industries to treat effluents before discharge.
In practice, these laws are routinely violated by public authorities themselves. It is telling that it took judicial intervention to spur any action: the National Green Tribunal in recent years has been cracking down, even slapping multi-crore fines on delinquent states.
In 2022, for example, the NGT penalized Punjab ₹2,080 crore for failing to prevent the flow of untreated sewage and other waste into rivers.
Several other states – Karnataka, Telangana, West Bengal and more – have faced similar rebukes and fines for the yawning gap in sewage treatment.
But imposing fines after the fact doesn’t resurrect a dead river or a child lost to dysentery. It only underlines how government bodies have neglected their duty for so long that courts must now step in.
To be fair, the government has not been entirely idle.
In the last decade mainly, ambitious programs and more funding have been directed at the sewage problem.
India’s sewage treatment capacity has increased by over 40% from 2014 to 2020, a significant jump in a short time.
The central government launched the Swachh Bharat Mission in 2014, which, while largely focused on ending open defecation by building toilets, at least brought sanitation into the national conversation.
Under Swachh Bharat and other schemes, over 70 lakh toilets were built in urban areas to expand access to basic sanitation. This was an important step – but it addressed only the supply side (toilets) and not the waste management side (sewers and treatment).
Consequently, more people use toilets now, yet much of the resulting sewage still goes straight into drains and groundwater, as the infrastructure to transport and treat it remains lacking.
Recognizing this gap, the government also ramped up programs directly targeting wastewater.
The Atal Mission for Rejuvenation and Urban Transformation (AMRUT), launched in 2015, invested heavily in urban utility infrastructure.
Under AMRUT, cities have laid new sewage lines and built treatment plants.
Over 1.49 crore household sewer connections were provided through AMRUT and related efforts, and an additional 4,174 MLD of sewage treatment capacity has been created so far under this mission.
This is not trivial – it means millions more homes linked to a sewage system and a substantial increase in nationwide capacity.
The Namami Gange program started in 2014, specifically focused on towns along the Ganga River, which is choked with sewage.
Under Namami Gange, 176 sewage treatment projects were sanctioned, with the aim of adding about 5,270 MLD of capacity for the Ganga basin.
Dozens of new plants and interceptor sewers have been built from Uttarakhand to West Bengal. A total of ₹32,898 crore has been allocated to clean Ganga, and 1,858 MLD of treatment capacity has been created so far under this program.
Separately, the older National River Conservation Plan (NRCP) has funded sewage projects on other polluted rivers, creating around 2,745 MLD of capacity in various towns.
Some state governments have also begun to wake up – a few states like Gujarat, Haryana, and Rajasthan have even formulated policies to recycle treated wastewater for use in industry and irrigation, trying to incentivize proper treatment.
In recent years, there’s been talk of a “circular economy” approach to water: treat sewage and reuse the water rather than dumping it. All these steps show that, at least on paper, the authorities acknowledge the problem and are trying to address it.
The trouble is that these efforts, while laudable, are nowhere near enough to match the scale of India’s sewage challenge.
The expansion in treatment capacity has continuously lagged behind the growth in sewage generation. Urban India’s population and water consumption keep rising, which means wastewater volumes climb each year.
The modest 4,000-5,000 MLD of capacity added under recent schemes is quickly overtaken by new sewage from millions of new urban dwellers and newly connected toilets. Even after the ongoing projects under AMRUT and Namami Gange are completed, India will still be treating barely half of its urban sewage.
The NITI Aayog’s own analysis found that even if all proposed treatment plants are built, about 49% of urban sewage will remain untreated (link below). In other words, if we fully execute every plan on the books, we would still be dumping half of our daily sewage into the environment.
That is a sobering realization.
It implies that the current approach is simply not closing the gap – we are running on a treadmill where the problem grows as fast as the solutions.
Furthermore, many of the new projects have suffered delays. For instance, Namami Gange has been slower than hoped – out of the 5,270 MLD targeted capacity, only 1,858 MLD (about 35%) was actually created by late 2022.
Some plants under construction have missed deadlines due to land acquisition issues, contractor troubles, or local opposition.
Meanwhile, existing infrastructure is ageing. Without diligent maintenance, today’s new STPs could become tomorrow’s broken-down units.
Financing also remains a concern: the upfront capital may come from government grants, but operating these plants year after year requires steady revenue for local bodies.
Many cities struggle to even pay electricity bills for running sewage pumps and treatment plants.
So, government schemes have poured money into building assets, but not enough to ensure they run sustainably in the long term.
Policy reforms have similarly been half-measures.
For example, while some states now have wastewater reuse targets, no national mandate forces cities to recycle or safely dispose of all wastewater.
The enforcement of water pollution laws primarily targets industries, but municipal authorities polluting rivers faced little accountability until the courts stepped in.
Swachh Bharat made India free of open defecation (on paper), yet we now face an even larger volume of contained waste with nowhere to go.
We needed a Swachh Bharat Part 2 focusing on sewage treatment, but the momentum didn’t quite carry forward at the same scale.
The result is that much of the positive impact of widespread toilet construction is undermined by the failure to treat the waste.
The government’s recent push for “ODF+ and ODF++” certification (which includes managing faecal sludge and sewage) is a step in the right direction, but many cities have only superficially met these criteria.
Tanker trucks might collect sludge from septic tanks, but often, they dump it in the nearest drain at night – a hidden scandal in many towns. It shows that policy loopholes and lack of oversight allow officials to declare success without solving the underlying problem.
Good plans on paper mean little if they’re not implemented earnestly on the ground.
The impact of all this extends beyond health and environment into the economy and social fabric.
Polluted water bodies raise the cost of providing clean drinking water – utilities have to spend more on treatment or go further to find unpolluted sources.
Farmers downstream of cities unwittingly use sewage-laden rivers to irrigate crops, causing contaminants to enter our food. One study estimated India’s agriculture suffers losses of around $1.2 billion per year due to yield impacts from irrigating with unsafe wastewater (link below). Fishermen who depend on urban rivers and lakes see their catch decline when fish cannot survive in oxygen-depleted waters.
Tourism and quality of life in cities take a hit when lakes catch fire (as happened to Bengaluru’s Bellandur Lake, fed by sewage) or when beaches are littered with sewage debris.
There is also a dignity and human rights dimension – it is often the low-income communities and, in many cases, specific marginalized castes who end up manually cleaning the sewage from clogged drains or living alongside overflowing sewers.
The failure to invest in proper systems essentially passes the burden to the poorest in the form of disease, lost livelihoods, and hazardous clean-up jobs.
Every angle you examine – be it public health, ecology, or economic efficiency – it becomes clear that letting 70% of sewage flow untreated is disastrously costly.
The country pays for it in hospital beds, dead rivers, and lost productivity.
India’s government, both at the Centre and in states, can no longer treat this as a low-priority issue.
The current incremental approach is not working, and the data makes that undeniable.
When only 1 in 4 litres of sewage is being treated, tinkering around the edges won’t fix it. We need a comprehensive overhaul of how urban wastewater is managed.
This means dramatically scaling up investment in sewage infrastructure – not just treatment plants but the whole network from household to disposal.
It means making sewage management a core function with dedicated funding for city administrations, similar to how big highway or metro projects are funded.
It means setting and enforcing strict timelines: for example, mandating that within the next 5-10 years, every city above a specific size must treat, say, 90% of its sewage, and backing that with financing and penalties. It also means embracing innovation.
Decentralized sewage solutions can help in dense or unplanned neighbourhoods where laying huge trunk lines is difficult; technologies like nature-based wetlands or smaller digesters could be deployed quickly to treat sewage at the community level. There are Indian startups and NGOs piloting such models in some cities, but they need support to scale.
Additionally, maintenance and skilled workforce must become a focus – building an STP is the easy part, but running it year after year is harder. Unless local bodies have the capacity and funds for proper operation, infrastructure will fail.
Public-private partnerships can be explored for operating sewage facilities, with performance-based contracts.
Crucially, governance accountability has to be strengthened.
Citizens have a right to clean water and a healthy environment under our constitution and laws. State agencies and urban local bodies should be held to account for meeting those obligations.
The public and media need to keep the spotlight on sewage treatment just as they did on toilet construction. It may not be glamorous, but it is lifesaving.
The hard truth is that the measures taken so far, while positive, have been too little, too late. The sheer growth of urban waste outpaces them.
The government often pats itself on the back for setting up a new plant here or a new policy there. However, when half of all urban sewage is still expected to remain untreated even after planned upgrades, it is clear that victory is nowhere in sight. We must call this what it is: a national emergency hiding in plain view.
India cannot afford to continue on this path.
Every year of delay means thousands more preventable deaths, more rivers turning into toxic sludge, and deeper costs to the economy.
Cleaning up our cities’ sewage will require money, yes – likely tens of billions of dollars of investment – but the status quo is already costing us dearly in health and environmental destruction.
In the long run, the benefits of proper sewage treatment far outweigh the costs. It improves public health dramatically, preserves precious water resources, and makes cities more livable. It also aligns with India’s global commitments to sustainability and development.
As the country urbanizes, this problem will only grow if not tackled head-on. We have seen some promising moves, but now they must be turbocharged into a comprehensive mission.
The fact that 70% of urban sewage goes untreated is a glaring sign of systemic failure, and fixing it is not just a technical necessity but a moral one. Indian cities need to stop treating their rivers and lakes as sewers.
The time for half-measures has passed – what we need is an all-out war on urban sewage pollution, backed by data, funding, and unyielding political will.
The health of our people and the fate of our water resources depend on nothing less.
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Best,
Jayant Mundhra
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References:
Well written and comprehensive analysis. Economist constantly considered supply and demand. It’s time to add environmental data on economic and financial reporting, as corporations are one side of solution. Local authorities and government agencies need activism and participation from citizens, both in time and effort, which can come from open data collection and reporting.
One of the biggest factors that is missing in this article is - the role of politicians (MPs/MLAs)/ local leaders/govt officials in urban planning. Development rules are flouted routinely for real estate gains, without consideration to civic amenities, sewage treatment, safety and security. Its a huge nexus of political and economic might vs what is right. Same goes with industrial waste and sewage. Tighten urban planning laws and implementation, thats a first step!