See picture above. This is a female cat which I found at a faculty in my university. Her end point of the right ear have been cut. You probably thought she might come into an accident resulting this. However it is not. This is a mark meaning that the cat had been captured, neutered and released which they are known as TNR cats.
The TNR (trap-neuter-return) is a method use to control the feral cat populations also on dogs. This method serve as alternative option for euthanasia method.
If you see this TNR cats...feed them..love them...and please don't remove them.