Uni admission

Hiiii
I will be applying to the following universities this year- LSE/UCL, St Andrews, Warwick, Edinburgh/Durham to study economics.
I am an Indian student studying in the CBSE board. In grade 10 I got an average of 91.4 per cent and in 12th grade I am expecting at least a 93 per cent. I have recently done an internship wherein I wrote a research paper and got it published on a youth journal. I have done many online courses and read books and papers by Tim Harford, Thomas Picketty, Gary Becker etc.. I will be elaborating what I have learnt from all this in my personal statement. I am part of a girl up initiative which has taught me about inequality and gender discrimination present in my country and how this effects the economy. I am going to receive an LOR from my internship mentor who is a professor in the university of Surrey. I also received an 8 in my IELTS.
Do I have a chance of getting into any of the unis mentioned above? I just want to be realistic.

Do you mean you are applying this September for 2022 entry - or do you actually hold offers for Sept 2021?

As an example, LSE's entry requirements are pretty tough. Do you meet them? https://www.lse.ac.uk/study-at-lse/international-students/country-pages/india

Read these :

How to Avoid getting 5 University Rejections : https://www.thestudentroom.co.uk/university/apply/how-to-avoid-getting-five-university-rejections
Applying for Economics : https://www.thestudentroom.co.uk/wiki/economics_degree

LSE requires 95 in 3 subs and 90 in 2 subs. I am confident that I will get the required scores.

As long as you get one of the 95s in Maths your application would be competitive.

Is this required for all the unis mentioned above?

I believe it is the equivalent of an A* in Maths in LSE's eyes - see the detail in that link I posted. Other unis are likely to be less exacting eg Warwick https://warwick.ac.uk/study/international/admissions/entry-requirements/india

Hiiii
I will be applying to the following universities this year- LSE/UCL, St Andrews, Warwick, Edinburgh/Durham to study economics.
I am an Indian student studying in the CBSE board. In grade 10 I got an average of 91.4 per cent and in 12th grade I am expecting at least a 93 per cent. I have recently done an internship wherein I wrote a research paper and got it published on a youth journal. I have done many online courses and read books and papers by Tim Harford, Thomas Picketty, Gary Becker etc.. I will be elaborating what I have learnt from all this in my personal statement. I am part of a girl up initiative which has taught me about inequality and gender discrimination present in my country and how this effects the economy. I am going to receive an LOR from my internship mentor who is a professor in the university of Surrey. I also received an 8 in my IELTS.
Do I have a chance of getting into any of the unis mentioned above? I just want to be realistic.

I don't have too much to add beyond what others have already mentioned. However, I would try to vary you pre-reading list a bit for when you write your personal statement. A lot of people will be mentioning reading things like Harford, Piketty, freakonomics, etc so I would try to think of some slightly more niche or academic titles to reference in your personal statement. They're good to still mention but you may want to add/change some titles to show some originality.

Oxford's PPE course provides a general economics reading list which you could check out and pick one, I'd avoid mentioning reading Krugman tho, he's a bit of a phoney. Most of the unis you're applying to have reading lists so you could check them out, obvious authors would be Stiglitz, Sen, Acemoglu, Keynes, Roth and others. These are more academic but there will be articles about them that are less formal for you to quote. Alternatively you could use evidence of maths reading to signal ability.

Perhaps this is a bit overkill but it worked for me and friends in getting us into top Econ undergrad programs so make of it what you will. Just don't be one of the thousands that quotes Adam Smith or something along those lines 😅 I would definitely talk about your research paper, lecturers will love that considering their whole career is about research so evidence of early research will likely play well as long as it's reasonable. Good luck!