The essay is too self-absorbed. You are always talking about what you can take from the university rather than what you can contribute. The whole essay should be about your contribution to the community. You were off to a good start when you discussed your Sikh upbringing. I was hoping to read more about how that upbringing would translate into your contribution to the Trinity College community. Instead, it veered into the "Myself" territory for most of the essay. Focusing on what you hope to learn and experience rather than what you can contribute. Paragraphs 2-5 are off track as far as I am concerned, as I know you will have a different opinion about what the actual focus of the essay is. However, I believe the focus should be on:
how do you see yourself contributing to the Trinity community?
Clearly paragraphs 2-5 do not focus on what you can contribute, just what you can take from the community. The mention of S.A.I.L. got you back on track, all the way to the end of that paragraph. Then, you dropped the ball again with your closing paragraph. Look into the community clubs and organizations of Trinity. There are many you can mention in this essay that will help you explain how you can bring your Sikh upbringing to the university, with a resulting happier community just because of how you were brought up. Your upbringing, properly explained in relation to the various clubs and organizations at the college will definitely help you explain how you can improve on the presentation of the 3 pillars, which seem to have a solid foundation in your Sikh upbringing as well.
Translate the langar into your participation at a soup kitchen or food bank, or any sort of community food support system the college might have, transform lives by teaching your college-mates about the Guru Granth Sahib and the inner peace that it can bring ( promoting meditation or something), I know the Sikh do not believe in proselytizing, however, I mentioned this only as a form of connecting and / or transforming the lives of those around you ( those who might need some sort of help or support, just an idea...) based on the requirement of the 3 pillars to "Engage. Connect. Transform." I believe your background perfectly fits the bill. You just haven't properly considered how to do it.
You need to show your potential to bring diversity to the college community while helping to promote a better understanding of your background. You have to show that your addition, based on your way of life, will be something unique that the community can benefit from. This time, it is not about you and what you can receive, rather, it is about you and what you can give.