Hundreds of saffron-clad Indian "sadhus," or holy men, protested in New Delhi Monday against plans to construct more than 50 dams on the River Ganges -- whose waters are sacred to millions of Hindus.

The sadhus, and environmentalists, say the dam projects -- which are linked to hydropower creation on the Ganges and its myriad tributaries -- will throttle the river at its source and threaten the natural ecosystem.

"Our mother river is being murdered by the government. It will dry up if all the dams are built,"said Swami Mukteshwar of the Ganga Mukti Mahasangram (Battle to Save the Ganges).

"The dams will slow the mighty river's flow to a trickle. Our holy water will be diverted and used to generate hydro power. This is shocking."

The sadhus pledged to lay down their lives to save the Ganges as a dozen of them started a three-day hunger strike at Jantar Mantar, a common protest venue in New Delhi

"Dams will be built over our dead bodies. They can mix our blood in the cement," said Swami Aseemanand, 65, who has been bathing in the Ganges for over 35 years in the northern state of Uttar Pradesh.

Hindus believe the Ganges' waters can wash away their sins and free them from the cycle of life and rebirth.

The 2,525 kilometre (1,568 mile) long river flows across five states.

A recent report prepared by the state-funded Wildlife Institute of India had recommended scrapping 34 of the Ganges dam projects, citing environmental concerns.

"The Ganges is in serious danger," Himanshu Thakkar, an expert on water management at the South Asia Network on Dams, Rivers and People research group in New Delhi told AFP.

"The construction of dams should be scrapped as they will cause irrevocable damage to the biodiversity," Thakkar said.