Tamil Nadu government has called a sand mining survey by IIT-Kanpur for the Directorate of Enforcement (ED) "illegal". The government says IIT-Kanpur has no right to work in Tamil Nadu. The ED asked IIT-Kanpur to check mining at 28 riverbed sites in October-November 2023. The survey claimed ₹4,730 crore worth of illegal sand was mined, much more than the ₹36.45 crore revenue recorded. Tamil Nadu's Water Resources Department asked IIT-Kanpur for details of the survey and the scientists involved. IIT-Kanpur's director replied that Professor Rajiv Sinha, who led the report, did not get leave for the survey period from October 7 to November 5. Rules say employees cannot leave without permission. The Tamil Nadu government told the Madras High Court that Prof. Sinha never visited Tamil Nadu for the survey and just prepared the report on paper. It said a private company, Terraqua Private Limited, started by Prof. Sinha and linked to IIT-Kanpur, actually did the survey. The state wondered why IIT-Madras was not chosen instead for the survey. It said IIT-Kanpur lacks legal jurisdiction as per the IIT Act, which limits IITs to their zones. The government argued that the ED and IIT-Kanpur-linked company acted beyond their authority. The report also noted drone rules were violated since no prior permission was taken from civil aviation or police authorities to fly drones for the survey. The Tamil Nadu government refuses to accept the survey results and calls them legally invalid.