Hey aspirant, when we talk about the toughest engineering branches that are mechanical and aerospace with chemical, electrical and computer engineering. These are the branches of engineering that are expected to be the toughest of all and it also give huge exposure. 

Hope this helps

Good luck 

Hello Bharath,
There is nothing as tough. If you want to do anything you have to take it easy only then you are able to do anything with interest and passion.If we talk about engineering it consist of several branches,every branch plays different role at their place.There is nothing we can say is tough but yes some of main branches of engineering are-
1-Computer Science and Engineering
2-Information Technology
3-Electronics and Communication Engineering
4-Electrical engineering
5-Mechanical Engineering
6-Civil Engineering
7-Chemical Engineering
8-Aeronautical Engineering