There definitely is a pollution problem on the mountain. They try to hide a lot of it from the tourists but we came across piles of empty plastic water bottles, tin cans, paper etc. The people that live in the country are the worst polluters. A lot of the people on the mountain are just trying to earn enough money to survive so the environment is not high on their priority list.
I think Nepal pays the sherpas $60.00 to bring down the old oxygen cylinders. Infact, our family was told to leave their empty cylinders behind. This is a way for the sherpas to earn extra money. Our outfitter encouraged people to use purification tablets or a water filter rather than buy bottled water.
In Nepal, the average yearly wage is $50.00 U.S. The developed countries are more environmentally conscience with their reuse, reduce and recycle programs but then they can afford to be. I am not making excuses for the tourists. There should be a pack in/pack out policy and maybe Nepal will adapt that in the near future or at the very least a garbage fee with the money paid to porters to bring the garbage off the mountain. The problem is what do they do with it once it is off the mountain?