Several experts believe the government has been following a flawed method of cleaning up the Yamuna. So when Delhi Chief Minister Sheila Dikshit reiterated recently that the river would not be cleaned up by the time Commonwealth Games are held, they felt this was only to be expected.

Manoj Misra of Yamuna Jiye Abhiyan said that the government is depending heavily on chemicals under the Yamuna Action Plan. "The government has not used any natural methods till now," said Misra.

Harsh Vardhan, an activist and bird enthusiast, points to the Mansagar lake in Jaipur as an example of how Delhi government can adopt an alternative course.

"The Mansagar lake is being cleaned through natural means. Wetlands have been created at several places to enable sewage water to flow through vegetation and get treated. Eco-based lake restoration is being attempted here, probably the first such example in India, and it is yielding positive results,” said Vardhan.

Wetlands are areas, such as swamps, marshes and bogs, where water either covers the soil or is present at or near the surface, particularly in the root zone, for a good part of the year, including the growing season.

Robert Oates, a Britain-based expert, agrees that the natural method can be adopted with success. “One thing that I am taking from India is the method of cleaning rivers and lakes through natural wetlands,” said Oates, director of the Thames River Restoration Trust, who was in India recently. He said though the Thames had been cleaned using chemicals and technology, the natural system is more sustainable.
The chemical processes, apart from using a lot of costly chemicals, also use up energy which further contributes to climate change. Wetlands in the area also help to cool the environment, Oates said.

Activists working on the Yamuna in India, including Himanshu Thakkar of South Asia Network on Dams, Rivers and People, concurs. “If you want to revive the river then it is essential to rejuvenate the area of wetlands. If the method being adopted to clean up the river has no connection with the local people and community, then it won't succeed,” Thakkar said.