Although BJP chief Amit Shah was earlier scheduled to address these rallies, his visit was cancelled and Gadkari was deputed in his place.
He also said she could travel by a boat through the river because the NDA government developed a waterway from Allahabad to Varanasi.
The items that would be auctioned include paintings, sculptures, shawls, pagris, jackets and traditional musical instruments from across the country.
There will be no discharge of effluents into the Ganga and its tributaries from grossly polluting units — distillery, sugar, pulp and paper and textile during the mela, said the CPCB order.
The Ministry of Water Resources, River Development & Ganga Rejuvenation have finalised the draft law.
Tree plantation will help recharge the groundwater which ultimately recharges the river through small tributaries.
The Yogi government had made it clear that no effluent would be released by the tanneries into Ganga in order to keep it clean for Kumbh Mela as the seers had threatened to boycott 'Shahi Snans'.
Gadkari, who was in the city to promote the cause of Ganga rejuvenation, had invited over 150 industrialists, chief executive officers and managing directors to discuss the issue.