India's environmental watchdog has fined a group headed by a Hindu spiritual leader 50 million rupees ($740,000) for building features that altered the topography and flow of the Yamuna River before a cultural festival this weekend.

The National Green Tribunal issued the verdict late Wednesday in response to petitions filed by environmentalists who say the roads, ramps and pontoon bridges could cause irreversible damage to the Yamuna floodplains.

The tribunal, however, allowed Art of Living Foundation leader Sri Sri Ravi Shankar to hold the festival on payment of fine.

Prime Minister Narendra Modi is scheduled on Friday to inaugurate the festival in which thousands of musicians and dancers are to perform.