Environmental problems have become exceptionally acute in the country. For a long time too little attention was paid to the environment. In effort to meet production goals the ministries stinted on measures to protect the environment from industrial pollution. As a result, about half of the water sources in the country are polluted with industrial or communal waste. In more than a hundred towns and cities with populations of some fifty million, the concentration of harmful substances in the air is over ten times the admissible level. For dozens of years the national economy focussed on large projects, including giant projects in what was called the transformation of nature. Blunders were committed that caused environmental disasters. Of the acute problems causing public concern the environment safety of nuclear and hydraulic power engineering is beginning to assume paramount importance. Public anxiety has grown particularly after the Chernobyl disaster. Another reason is the adverse effect of flatland hydropower stations on the environment. The list of serious environmental problems could be continued. In recent years people have become more sensitive towards the environment. Still more public organisations and unofficial environmentalist movements have been established with every passing year. In 1987 a "Green Peace" public commission has been set up. Its main goal is to combine the people's efforts for peace with the huge and ever mounting movement for nature conservation. Another area of its work is to set up and strengthen co-operation among environmentalists from many similar organisations abroad. "Travels for Peace and Nature" is the name of another public movement that appeared in Russia some years ago. It concentrates its efforts on theory and practical work. The movement launches all kinds of environmental actions and informs the public of the ways, means and results of this work. Russia is co-operating in the field of environmental protection with the United States, Canada, Norway, Finland and other countries. Russia and the United States are carrying out joint projects to study and protect the environmental systems of the Arctic and Subarctic regions, and also to study some of the natural processes in the permafrost zone.