Why is life so hard in our planet? Why So much sickness

I agree with all the answers, you know what I'll answer this Ques with the other one.

This depends on how your mind percieves the world. But really, sickness is because of what we eat and breathe in on a daily basis.
The world is polluted of corrupted selfish people and oil

Nothing to do with the planet. People, only people. How many of your so called "sicknesses" are self induced? Own fault!
Peace.

Because human are naturally greedy