The estimate of 170,000 drill holes around the country does not include the illegal ones, most of which are in Attica. Elsewhere, the prefectures with the greatest number of drill holes are the Argolid (with over 24,000 bores, although not all are active), Corinth, Viotia, Fthiotida, Arta, Karditsa, Larissa and Magnesia. Attica has the most drill holes for urban use, followed by Thessaloniki, the islands of Syros and Paros, the prefecture of Lasithi on the island of Crete, and Naxos. Most island water tables are as full of holes as a sieve, particularly on the Cycladic Islands, where there are more private bores than public ones. On Paros, there are 50 municipal wells and 250 private ones, on Tinos 30 municipal wells and 150 private ones, on Syros 40 municipal ones, while the three desalination plants compete with over 300 private boreholes. In many cases, the consequences of over-drilling are already visible. Scientists from the Institute of Geological Exploration (IGME) believe that coastal groundwater is at immediate risk of adulteration by seawater (that has already happened on over 176,000 hectares around the country, most of all in the Argolid). They say that while the procedure for issuing permits and monitoring drills remains so flexible, the situation will deteriorate to the point where it will become irreversible. «In their efforts to find more groundwater, many are drilling deeper and deeper,» said Panayiotis Sabatakakis, a hydrogeologist at IGME and member of the International Association of Hydrogeologists. «In Thessaly, about 13,000 bores have reached down to over 300 meters. On Naxos they have gone beyond 400 meters, in the Argolid and at Velestino in Magnesia, to 300.» Over-drilling not only causes salination (when the sea infiltrates the water table – the areas where this has happened is shown on the map) but the subsidence of the soil. Thessaly is a typical example where in many places the earth has subsided catastrophically. «The first signs that the water table had been depleted appeared in the 1980s,» said Sabatakakis. «As the real effects were not immediate, political officials in the prefecture left the real decision making to the next term.» Despite efforts to reduce waste, the Thessaly Plain still accounts for huge amounts of water consumption. This is particularly evident given the fact that in Israel they need just 1.5 million cubic meters of water a year to irrigate an area over twice the size of the Thessaly Plain, where 1.68 million cubic meters are used.