THE increasing global concern over the environment has become a vital part of the Dutch Government's policy. Last year, on the 25th wedding anniversary of Queen Beatrix and Prince Claus, the Royal couple said that those who wished to present them with a gift could best do so by planting a tree. ''A silver wedding with a green border,'' Queen Beatrix aptly worded her wish. The Netherlands' concern over environmental issues is understandable. Its geographical position in Europe has made it particularly sensitive to ecological problems both at home and abroad. The country lies on the delta of three major European rivers - the Rhine, the Meuse and the Scheldt. Since pollution recognises no national frontiers, The Netherlands is affected by pollution from some other countries in Europe, just as pollution from Holland affects other states in the continent. Lying as it does at the delta of these three major rivers, cross-border pollution affects, and continues to threaten, drinking water supplies, about one third of which is dependent on surface waters. Like water, air pollution does not stop at national boundaries. About 60 per cent of the acid rain in The Netherlands is caused by other nations' pollution, just as much as a substantial proportion of the country's own acid emissions end up in other countries. There are other problems, too, with international ramifications, such as the depletion of the ozone layer and the greenhouse effect. The transnational nature of the problem confronting Earth has increasingly convinced governments and people that no country is an island, that secure national frontiers will not insulate a nation from the devastating effects of pollution. These effects might not always be felt by this generation. But, if this generation does not take concrete steps to deal with the complex issues now, succeeding generations may well find this planet uninhabitable. It is a question of survival and this is what makes the Dutch so involved in both domestic and international environmental issues. While cleaning up its own environment, the Dutch Government is pressing for greater international efforts so that Europe and the world can be a safer place in which to live. It is pressuring the European Community to adopt official positions in global environmental talks. ''During the talks on the Maastricht Treaty, The Netherlands called for the community's environment policy to be given new impetus and to be extended beyond the borders of the EC,'' said Mr Piet Dankert, State Secretary for Foreign Affairs. The Netherlands has prepared ambitious environmental plans such as the National Environmental Policy Plan (NEPP) and the National Environmental Policy Plan Plus, which updated the original document. The NEPP motto, The Environment: choose it or lose it, succinctly states the urgency of the problem, for The Netherlands. ''With a population of almost 15 million and a surface area of only 41,548 square kilometres, the ecological balance in Holland is delicate and easily disturbed,'' said Mr Marius Enthoven, director-general of Environmental Affairs for the Ministry of Housing, Physical Planning and Environment. ''A clean, healthy environment is one of the basic conditions for quality of life and is an absolute necessity for continued economic growth.'' The NEPP, which tries to find long-term solutions to Holland's environmental problems, is based on two important environmental reports. One is the Brundtland Report, named after the head of the special United Nations Commission which studies the subject. The other is Concern for Tomorrow published in 1988, a year after the UN report, by Holland's National Institute of Public Health and Environmental Protection. The Brundtland Report, which addressed environmental issues from a global perspective, was the first document to define the goal of sustainable development, which meets the needs of the present generation without compromising the ability of future generations to meet their own needs. The report also underlined the growing inter-relationship between the world economy and ecology and said the health of one was crucial to the well-being of the other. Both of these perceptions have been incorporated into the philosophy of the NEPP, which contains tough measures for the period between 1990 and 1994 as well as charting the course of environmental policy in The Netherlands until 2010.