Hi Anushka,
Let me make you something clear about IIT'S. People think that if you get into an iit you will definitely get a good job. Definitely you have a good pool of opportunities but that is not everything. If you will take ocean engineering then be prepared for the hard work. You have to learn several skills and also you have to keep your grades high to finally land on a good job offer. On the other hand if you take ece then you will have much more options. At last I would say that branch matters. If you are sure that you will do hardwork then you can pursue ocean or mining engineering, there will not be any problem but I would suggest you to please try to get a better branch even if you have to go into new iit's. Nobody knows what will happen in future but you must take such option which has lesser risk. Lastly choice is yours as you know yourself better than others. I am also from iit and i am suggesting you this according to my experience till now.
All the best!
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