Sand mining, especially illegal sand mining in Tamil Nadu state is done on river beds, basins and beaches, It has been on an increase, since the beginning of the 1990s following a boom in the construction industry. Palar River basin, Vaigai River basin, Cauvery River basin (including its tributaries) and Thamirabarani River basin are some of the most affected regions. Illegal quarrying is happening in these areas in broad daylight. Though as per Tamil Nadu Public Works Department, 5,500-6,000 truck loads of 200 cubic ft. of sand is mined each day, in reality this figure is estimated to be around 55,000 truckloads of 400 cubic ft. of sand per day. In 2013, illegal sand mining in the state was estimated to be worth . This also results in the state exchequer losing over in revenue. History River sand mining began in the state as a small scale unorganised activity in the 1980s. It quickly began to boom in late 1980s and the beginning of the 1990s owing to a boom in real estate and construction. During the late 1980s the industry was mostly under the control of small local politicians, but political parties soon found sand mining to be a very lucrative source of revenue, hence by the beginning of the 1990s district level politicians soon emerged as major decision makers in the industry and permits were given on partisan lines and became very contentious. The AIADMK government during the 1990s amended the rules to allow granting of mining leases without any auction, this continued even after it was voted out and replaced by a DMK government. This practice led to political parties giving leases to a small group of miners affiliated to them, and allowed the party high command to bypass local leadership. This practice was ended by the Madras High Court in 2001 when it cancelled all such leases granted without an auction. In 2003, the then state government under the AIADMK brought all river sand mining under the Public Works Department (PWD), in practice however the PWD did not have the necessary capacity to meet the demand for river sand, this led to it subcontracting the mining, loading and unloading to private contractors after an auction. The PWD also failed to carry out the necessary inspections, and many of the contracts continued to be given to the previous group of private sand miners who had formed cartels,