"We hold respondent no. 3 (Art of Living) responsible for the damage to the Yamuna floodplains," green tribunal head Justice Swatanter Kumar said in his order.
The verdict comes after a report by an environmental experts panel accused the organisation of causing extensive damage to the Yamuna floodplains in Delhi during the World Culture Festival in 2016.
The green court has already fined the Art of Living Rs 5 crore for the damage and said the amount would be used to restore the fragile floodplains.
"In case more funds are required, Art of Living will have to pay," the green court chief said. However, if restoration costs less, the remaining amount of the already deposited Rs 5 crore will be refunded.
The green court also asked the capital's lead planning body, the Delhi Development Authority, to do a fresh assessment of how much money would be required to restore the damaged floodplains.
Environmentalists had vocally objected to organising the World Culture Festival on the ecologically fragile Yamuna banks -- which included a 7-acre stage for 35,000 musicians and dancers, newly built dirt tracks and 650 portable toilets across 1,000 acres.
The Art of Living has denied it caused any damage to the banks and says it will approach the Supreme Court.
"The judgement is erroneous and untenable. Our submissions have not been considered at all. It is important to note that one of the judges recused himself from the bench just before the judgement was pronounced. We will appeal to the Hon'ble Supreme Court. We are sure that we will get justice there," a statement by the Art of Living said.