My budget is up to 50,000 INR I want to buy a dslr with lens 18- 135mm approx..

Here is a thread you can look at that has lots of choices and explinations.

https://www.askmehelpdesk.com/photography/confused-cameras-754754.html

If you have enough experience with dslr then buy one but if not then take a short course first. Nikon, sony, fuji, canon etc are good.