Reviving urban drains: From sewers to pristine streams
This article is authored by Prashanth Suresh Kumar and Malini Balakrishnan, Centre for Water Security, Plaksha University.
How often have you come across a stream of polluted water while traveling through a city? In India, these urban waterways—locally known as nallahs—are essential components of city infrastructure, designed for stormwater drainage, recreational use, or even as natural water bodies. Yet, instead of serving their intended purpose, many have now turned into open sewers, carrying untreated sewage, industrial effluents and solid waste.
One such stream is the N-Choe, originating in Chandigarh and flowing through Mohali before merging into the Ghaggar River. Residents living along its banks experience foul odours, littered garbage, and the presence of untreated sewage directly discharged into the stream. Some surrounding settlements rely on its water for agricultural purposes, exposing them to various health risks. Moreover, pollutants from the N-Choe can travel downstream, threatening larger water bodies and ecosystems.
Despite repeated complaints and regulatory notifications—such as directives from the National Green Tribunal to the Punjab Government—effective management of the N-Choe remains elusive. This raises a crucial question: Who is responsible for fixing this? While municipal bodies and pollution control authorities are often at the center of scrutiny, the challenge is complex and requires a collaborative solution.
It's worthwhile to look at successful urban drain revitalisation projects both in the international and national context. One of the famous examples worldwide is Cheonggyecheon, South Korea. Once a neglected, polluted waterway in the heart of Seoul, Cheonggyecheon was transformed into a thriving 10.9 km long urban stream through a large-scale restoration project. The initiative improved water quality, reduced urban heat, and revitalised the cityscape, turning the stream into a public space that attracts locals and tourists alike. In India, the K100 project in Bengaluru set an example by restoring a 9.2 km stretch of the Koramangala stormwater drain. The initiative involved desilting, bioremediation, and the integration of technology like water-level sensors and automated gate closures to prevent overflow during heavy rains. What was once a sewage-filled drain is now an eco-friendly corridor with walkways and green spaces.
Advancements in technology have played a key role in both the projects. In this context, universities and technological/research institutions can play a pivotal role in tackling this crisis. For instance, Indian Institute of Technology (IIT) Kanpur is currently leading efforts to rejuvenate the Kushak drain, conducting analysis on the polluted water, and suggesting water treatment technologies to restore its ecological function. Similarly, research institutes situated near other urban drains can play a role in helping the local government abate the pollution. These can be through:
- Better problem identification which includes conducting studies to map pollution sources, identify contaminants, and analyse water usage patterns
- Suggesting technological innovation to help develop cost-effective treatment solutions and waste management systems
- Promoting community engagement through education and awareness building for local populations in topics related to water conservation and responsible waste disposal practices
- Providing data-driven recommendations for sustainable urban water management policies.
By becoming active players, involving local citizens and partnering with the local government and pollution control authorities, the research and educational institutes will promote a collective ownership of these crucial waterways. This will further support the government’s efforts to rejuvenate various rivers via infrastructure-oriented solutions such as building centralised sewage treatment plants and sewerage network. By shifting from complaints to collaboration, we can reclaim these crucial waterways, turning polluted nallahs into thriving urban streams.
This article is authored by Prashanth Suresh Kumar and Malini Balakrishnan, Centre for Water Security, Plaksha University.
