Sorry that I have not been able to answer your comment earlier, @kamchore!

I agree with a lot of what you are saying. Wildlife tourism can be really good for both humans and conservation efforts, but I'm not sure it's always the best for the animals. As you say "Tourist also love to feed animals with their hands which passively make a close relationship between animals and humans". I also think it is really cool to feed animals by hand, but I also believe that we should let the animals be able to stay wild, and not become too familiar with humans. How will they escape hunters if they think the humans are there to feed them?

However with all the pros of tourism there are few cons like hydro carbon pollution due to automobiles,throwing plastic garbage etc

Good point. And even more emission from planes; these pollute an extreme amount!