Army has spent more than a week building two bridges which will float on the River Yamuna for the event, which is expected to draw 3.5 million people to the banks of the river and will be opened by Prime Minister Narendra Modi.

Army sources who asked not to be named confirmed to NDTV that 120 personnel were assigned to build the bridges, and that after expressing reservations about the task, senior officers made it clear that the organizers must accept liability for any accident that injures attendees.

Government sources said the organizers - Sri Sri's Art of Living Foundation - will be billed for the Army's costs, and that its help was sought because of safety concerns including worries about a stampede, and the attendance of the Prime Minister.

The World Culture Festival, a three-day event, will do serious damage to the delicate ecosystem of Delhi's Yamuna River, activist Anand Arya alleges. He has asked the National Green Tribunal to cancel the festival, which is meant to start on Friday.

President Pranab Mukherjee, who had earlier agreed to attend the opening, along with the PM, on Monday conveyed that he will not be present.

Sri Sri's Art of Living foundation says the event will feature yoga and meditation sessions, peace prayers and traditional cultural performances from around the world.

Sri Sri's Art of Living foundation has denied there will be any permanent impact and says it has secured permission from all the necessary authorities to hold the event. "We have used only eco-friendly material like wood, mud, cloth, and scaffolding towards building a temporary stage," the foundation said in a statement.

"We should be given the red carpet, and awards for organizing the event," said Sri Sri to NDTV, declaring that his intent is to build awareness of the urgent need to clean up a highly contaminated river.

Sri Sri, once ranked by Forbes magazine as India's fifth most powerful person, is seen as close to PM Modi and the pair have meditated together.