Water Pollution

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Across
  1. 3. Public place covered in sand.
  2. 5. Black substance used to make engins work.
  3. 6. A big boat on wich people live for some days.
Down
  1. 1. Animals living underwater.
  2. 2. Trowing trash in bins made for that type of trash.
  3. 4. When there are too many people in the same place.
  4. 7. Bottles are made from that material.