Source 4

http://en.wikipedia.org/wiki/Environment_of_China
1. The source comes from an online encyclopedia of information called wikipedia.
2. There are many authors.
3. Their credentials are that they did lots of research and showed their sources.
4. This source explains the many ways china's pollution and in general their environment are having issues.
5. Yes.
6. I believe this source because it is well-researched and shows its sources.