1. What are the causes of air pollution?
2. What are the causes of water pollution?
3. What are the causes of land pollution?
4. What are the effects of air pollution?
5. What are the effects of water pollution?
6. What are the effects of land pollution?
7. What should we do to reduce air pollution?
8. What should we do to reduce water pollution?
9. What should we do to reduce land pollution?
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