Shorten the English text 3 times to retell it. Without losing the main points and ideas of the text: "1
One of the most urgent environmental problems in the world today is the shortage of clean water. Table I shows the causes of the water shortage. There are large differences in per capita water consumption between different countries. A comfortable lifestyle (with flush toilets, washing machines and public swimming pools) uses a lot of water. A lavish lifestyle (with automatic car- wash machines, Jacuzzis and backyard swimming pools) uses many times more. The average Kenyan uses five liters of water a day; the average American uses 1,000. More and more people in the world are adopting a Western lifestyle. So even if population growth stops, the water shortage will get worse.

2
Access to clean drinking water is a basic human right. But acid rain, industrial pollution and sewage dumping have made many sources of water undrinkable. Lakes, reservoirs and even entire seas have become vast pools of poison. Lake Baikal in Russia is one of the largest lakes in the world. It is also one of the most beautiful. The local people call it the Holy Sea. It contains a rich variety of animals and plants, including 1,300 rare species that do not exist anywhere else in the world. But they are being destroyed by the massive volumes of industrial effluent which pour into the lake every day. Until very recently, environmental standards in the former Soviet states were much lower than in the West. Even where laws existed, the government did not have the power to enforce them. Most industries simply ignored the regulations. In the past few years, glasnost has given people greater freedom of speech. They are now free to protest about the pollution. Some factories are now disposing of their waste more responsibly. But many others still pour untreated industrial waste into the Holy Sea.

3
The Mediterranean Sea occupies 1 percent of the world's water surface. But it is the dumping-ground for 50 percent of all marine pollution. Sixteen countries border on the Mediterranean. Almost all of them regularly dump shiploads of industrial waste a few miles offshore. Sewage effluents pour into the sea only meters from popular bathing beaches. In 1975, the United Nations Environment Program brought together these 16 countries and drew up the Mediterranean Action Plan. The countries agreed to stop dumping from ships and to reduce sewage pollution. Few, if any, of them have kept their word. In the 1950s, Japanese factories dumped waste containing mercury into the sea at Minamata Bay. Shellfish became contaminated with this very toxic heavy metal. Over 2,000 people developed brain damage and 40 of them died. These tragic examples should teach us that the ocean is neither a garbage can nor a toilet.

4
Sewage is a rich source of micronutrients, which are essential for the growth of plants and animals. Sewage sludge and fertilizers washed off the land increase the concentration of micronutrients (particularly nitrates) in the sea to dangerous levels. Plankton (tiny plants that float near the surface of the water) become so numerous that they cut out the light to deeper parts of the sea. This endangers plants that grow on the sea bed, which need the sun's light for photosynthesis. Seaweed is also very sensitive to changes in the level of micronutrients in coastal waters. One or two species of algae (seaweed) can outgrow all the other species. Overgrowth of algae can cause slimy, smelly, ugly deposits on beaches. Occasionally algae produce poisonous toxins that can kill fish or cause skin rashes in swimmers.

5
We condemn deliberate pollution of the water supply by industrial waste and sewage dumping. But we are usually impressed by "developments" such as huge dams, dikes and irrigation schemes. These are often magnificent feats of civil engineering. They cost a lot of money and use modern materials and equipment. We often assume that the people who plan and build these systems know what effect they will have on the environment. In fact, many dams and irrigation schemes have been environmental disasters. Three quarters of the world's water is used to irrigate crops, so inefficient or extravagant irrigation schemes can cripple a region's water supply. The Aral Sea in Russia was once the fourth-biggest lake in the world. It is now less than half the size it was in 1965. Badly-planned irrigation schemes have taken water from the rivers that fed the Aral Sea. In addition, overuse of pesticides on the cotton crops nearby has polluted the water with toxic chemicals. In some cases, major water diversion projects began because a new technology became available and governments wanted to demonstrate their new-found power over nature. Dams can also be a direct political tool. Rivers often flow through one country to get to another, so the first country can potentially control the flow of water into the second. Turkey has recently built several dams across the river Euphrates, and has already used these dams to restrict the water flowing through to Iraq and Syria. It has also signed an agreement to sell water to Israel.

6
"Development" projects can also make soil erosion worse. Forests and grasslands in a river valley soak up water after heavy rains and slowly release it back into streams and rivers. This prevents the valley from becoming dry and dusty in the months without rain. In addition vegetation also prevents erosion by holding the particles of soil together. If there is no vegetation, the soil crumbles away and is washed into the rivers as silt. Rivers become clogged with sediment. Lakes change from clear, blue pools into thick, muddy puddles. The destruction of rainforests and intensive farming practices (such as heavy grazing of cattle and excessive plowing with powerful machines) both increase soil erosion. Because of deforestation and modern farming methods, the sediment load of the Yellow River in China is 1.6 billion metric tons per year, and that of the Ganges is 1.455 billion metric tons. The traditional farming methods used by primitive communities may seem inefficient, but the sediment loss from these methods is tiny.

7
The best things in life are free. But because water is free, we often take it for granted. A few years ago, people thought that the supply of clean water in the world was limitless. Today, many water supplies have been ruined by pollution and sewage. Others have dried up because we have diverted the water for hydroelectricity or badly-planned irrigation projects. The destruction of forests and grasslands has increased soil erosion. Clean water is now scarce, and we are at last beginning to respect this precious resource. Like other environmental resources, the clean water that remains is the property of our children and grandchildren. For their sake, we must fight to protect what is left of the water supply."