Urban Sanitation Challenges in India: Shift towards Decentralized Solutions
KAKALI DAS

Despite being linked to numerous negative health outcomes, poor sanitation remains a significant challenge in the 21st century.
Rapidly expanding megacities continuously increase the demand for clean water, much of which is sourced from hundreds of kilometers away. After use, this water is often discharged into rivers without undergoing any treatment.

This unchecked discharge is transforming our rivers into open sewers, aggravating the twin challenges of water stress and the climate-induced intensification of the water cycle. These factors are further straining our already inadequate water and sanitation infrastructure. Additionally, the growing presence of large informal settlements is compounding the crisis by increasing both water demand and wastewater discharge.
According to the Central Pollution Control Board (CPCB), India currently generates approximately 70,000 million litres of wastewater per day (MLD). However, most cities lack the necessary infrastructure to effectively manage and treat this wastewater.
Let’s take a closer look at the situation. Our sanitation systems, often referred to as “flush and forget,” are modelled after those in developed countries. However, they rely heavily on large volumes of water to function effectively, making them unsustainable in water-scarce conditions.
Despite the presence of these systems, they demand extensive operations, maintenance, and frequent repairs due to clogging. The situation is even more critical in dense informal settlements, where basic infrastructure is either inadequate or entirely absent.
The irony lies in the fact that our densely populated informal settlements rely on non-sewered systems, which are not connected to centralized sewer networks, while affluent and planned colonies benefit from well-established sewered systems.
According to the 2011 Census, out of nearly 8,000 cities in India, only 10% have sewered systems, and even those are only partially developed.
Urban India’s sanitation challenge is compounded by rapid city expansion and growing populations driven by migration and other factors. To address this, we need a combination of systems that can effectively serve both planned, privileged areas and the underserved peripheral settlements.


The second major challenge for urban sanitation is that 40% of India’s total land area—not just urban areas—falls within semi-arid and arid zones. Climate change and water stress further diminish the feasibility of traditional sewered systems. Moving forward, decentralized, non-sewered solutions tailored to local contexts should be prioritized.
Decentralized systems are less resource-intensive and can function without extensive sewer networks by transporting sewage or septage to localized treatment facilities. These systems also promote greater equity and justice, ensuring that both privileged and underserved settlements have access to proper sanitation and treatment solutions.
Another advantage of decentralized sanitation systems is that the waste processed through these treatments can be reused locally, including both treated wastewater and biosolids, making the reuse highly effective.
Since 2017, India has implemented a national policy for faecal sludge and septage management, resulting in the establishment of over 500 faecal sludge treatment plants across various states. The Centre for Science and Environment (CSE) has conducted a study on 69 of these treatment plants.

In 2022-23, the faecal sludge treatment plants built in India were found to be as effective as septage treatment plants in treating wastewater, with their performance typically evaluated based on BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand) levels in the treated water.
The real challenge in making faecal sludge treatment plants operational is ensuring a consistent and adequate supply of septage to these facilities. This issue does not stem from a lack of septage, but from the difficulty of extracting septage from septic tanks at the household level and transporting it to the treatment plants. This remains a significant challenge.
To address the challenges of urban sanitation in India, we need a combination of various treatment systems—centralized, decentralized, sewered, and non-sewered.
What is most important is that these treatment systems are planned with a long-term perspective, ideally for 20 years or more, tailored to each state and city. Without such long-term planning, it becomes challenging to ensure the most effective use of resources.
Traditionally, treatment standards have been set to prevent the pollution of water bodies, such as rivers, from industrial and human waste. As a result, these standards are primarily focused on protecting water bodies and not on the reuse of treated sludge. However, the standards need to be revised to ensure they are suitable for reuse, without being so stringent that they are only applicable to water body protection.

The immediate priority is to ensure that faecal sludge treatment plants, wherever they exist, become functional and operational. For this to happen, desludging must be carried out, and desludging can only be successful if it is incentivized and supported, either as a public service or as a private business.
We should prioritize decentralized systems wherever possible, and the Centre for Science and Environment (CSE) has been advocating for this approach over the past 15 years, particularly since the formulation of the last five-year plan.

The final priority is enhancing the capacities of our institutions. Most of our technical institutions at the state and national levels are heavily focused on engineering, particularly in centralized sanitation systems. There is a significant need to bridge this gap by training our officials, policymakers, and technical staff in the design and implementation of decentralized and non-sewered systems.

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