Do you think rivers are as clean now as they were 20yrs ago. Has polluted water become an increasing problem?

Question: Do you think rivers are as clean now as they were 20yrs ago. Has polluted water become an increasing problem?
- Keywords:
  clean,
  pollution,
  problem,
  river,
  water
Asked by Pheonix to Golnaz on 8 Nov 2017.
- Golnaz Ezzati answered on 8 Nov 2017:
  
  They are definitely not as clean as hundreds of years ago! But during the last decades, they have become polluted in various degrees in different parts of the world. But the goal is to get the clean again in coming years.

Question: Do you think rivers are as clean now as they were 20yrs ago. Has polluted water become an increasing problem?