THE hitchhiker was a 19-year-old economics student in Prague heading home to the northwest city of Teplice on the Czechoslovak-East German border. It was a cold, blindingly foggy day. As the car crept slowly forward, conversation turned naturally to the weather.
``Teplice had a terrible time at the end of October,'' the young woman says. ``There was dense, orange-gray colored smog all over the city. People were told to stay home except to go to work. Schools were closed and operations were forbidden in hospitals. It lasted a week.''
Teplice, the northern Bohemian town once renowned as Czechoslovakia's oldest spa resort, is in the heart of the most polluted region of a seriously polluted country.
In the rolling landscape nearby, huge open-cast coal mining has created ``moonscapes'' of hillsides and acid rain from heavy industry has turned vast areas of forest into stretches of broken branches and dead stumps.
Smog emergencies are routine throughout the winter, when heating plants spew out fumes from low-quality coal, and conditions are judged so detrimental to health that workers in the area are given financial compensation for living in a dangerous zone.
Deterioration of the ecology has been one of the major concerns of the opposition groups that ousted Czechoslovakia's hard-line Communist leadership. Even before the mass demonstrations of the last three weeks, it had touched off isolated protests in towns around the country.
Ecological disaster looms over large parts of Czechoslovakia and the threat, which has been growing for decades, was something that all elements of Czechoslovak society - from the former hard-line Communist authorities to opposition groups - recognized. It is also something no one quite knows how to confront.
``Ecology not only could be but should be the movement around which all people should be united,'' says a Prague scientist associated with the intellectual opposition.
Lack of money is the main overall obstacle in solving the ecological problem,'' says Jiri Nechvatal, deputy director of the environment department of the State Commission of Scientific and Technological Progress.
A recent major government report sounds like a war bulletin, focusing on a decline in life expectancy induced by pollution and rising rates of illness as well as damage to nature.
``Over the past 20 years, the quality of all components of the environment sharply deteriorated, practically throughout the territory of our country, and in some localities, particularly in North Bohemia, in Prague, and Bratislava, the situation is critical,'' it said. ``Forests are dying to a critical extent over large areas of the territory, and a number of plant and animal species are endangered and face extinction.
``The impact or environmental damage on the national economy is estimated to represent a loss of 5 to 7 percent of the national income,'' it added.
A related report last month by the official CTK news agency pointed out that things are getting worse: ``A forest ceases to be a basic renewable source in Czechoslovakia.'' Changing this dire forecast, it added, could only be achieved by cutting ``the volume and toxicity of emission or pollutants into the air by at least 50 percent.''
Curtailing or cleaning up Czechoslovakia's mining and heavy industry - the backbone of its economy - to that extent would mean such drastic economic reorganization that, even if the money and means to carry out such changes were available, the restructuring might end up triggering economic collapse.
``The problems are very complex and very difficult,'' says Mr. Nechvatal. They also have not sprung up overnight.
Before World War II, Czechoslovakia was one of the world's top 10 industrial powers. Under communism, its position plummeted. Much of its industry and factory infrastructure is outdated. New factories have also been built in unsuitable places, such as near historic towns and natural beauty spots, for political reasons.
``To illustrate the depth of the problem is the fact that the first problems with industrial exhalations [acid rain] were reported in the 1870s,'' says Nechvatal.
``Many neighboring countries started to deal with environmental problems 20 to 30 years ago,'' he adds. ``Unfortunately we in Czechoslovakia didn't care about them from the beginning. We neglected them, and we only started to discuss them around 1980. That's why the situation is so acute now.''