Atomsphere
We breathe oxygen to live. Air pollution is a major problem, not just in big cities.

Animals
Animals are an important part of our ecosystem. Many animals are now endangered.

Land
Landfills leak dangerous chemicals into the ground, and illegal dumping can make land useless.

Trees
Erosion can happen when nothing holds soil together, so trees are very important.

Water
All life needs water to live, so water pollution is a serious problem.