I want to know the answer to the following question:
What is one thing that helped to improve condition of forests, rivers and air?
All the background I'm provided with is that "Today's environmental problems are the salination of the Werra river, caused by discharges of K+S salt mines around Unterbreizbach and overfertilisation in agriculture, damaging the soil and small rivers.". Is that enough to answer the question?
Answer: no