The Buddha Nullah is a seasonal stream that runs through Ludhiana and into the Sutlej. It was a nullah carrying monsoon runoff. It now carries the city's untreated sewage and the effluent of its dyeing and electroplating industry.
Downstream of the confluence the Sutlej carries heavy metals, dyes and organic load past villages that take drinking water from hand pumps into the shallow aquifer.
Successive clean-up projects have been announced and funded since the 1990s. Treatment plants have been built and have run below capacity or not at all. The nullah is one of the most studied and least improved pollution problems in India.
Villages downstream have documented health complaints and have petitioned repeatedly. The Kali Bein restoration at Sultanpur Lodhi, done by volunteers on a much smaller stream, is the standing reproach to it.
It is a solved engineering problem that has not been solved politically for thirty years.
It is a seasonal stream that once carried monsoon drainage into the Sutlej. It now carries the discharge of a city of nearly two million and several thousand industrial units.
The dyeing units are the largest single contributor and the colour of the water changes with the shift. Cleaning projects have been announced repeatedly since the 1990s and budgets allocated several times.
It joins the Sutlej above the Harike headworks, which is the intake for the canals into Rajasthan, so Ludhiana's effluent reaches drinking water eight hundred kilometres away.