Hey ,

At first many many congratulations for your success in JEE MAIN 2020. Now I'm going to answer your query about the academic and placement review of the top 4 IIT institutions in India according to their rank:
1. IIT Madras :
Academics: It focuses on student's analytical and logical thinking, innovative ideas, hands on problem solving, research work etc. Their faculty and management also organises symposia, several technical conferences and workshops , special lecture for various academic related topics under Extra Mural Lecture Series. And all the faculties are very much approachable, well - equipped and are being awarded several times from different national and international organizations in their academic careers.
Placement: Almost 246 renowned companies visit this campus every year and almost 90% students get placed in those companies with mind-blowing packages. The highest salary offered here was 1.33 crores per annum till date and most importantly the average salary is 16.1 lakhs per annum.
Top Recruiters: Intel , Tata Consultancy Services ,Micron Technology India Operations , VMock India , Standard Chartered GBS India , Citi, Microsoft India, Mastercard , Axis Bank , Flipkart , Tiger Analytics , Samsung R&D, Bajaj Auto , Wells Fargo EGS India , and Mercedes Benz R&D , L&T Construction , Goldman Sachs and Bajaj Finance Ltd .
2. IIT BOMBAY:
Academics: Their faculties are extremely cooperative, flexible, enthusiastic, open-minded and very much student-friendly. Also by regular basis class tests, professors encourage all the students to engage themselves in question-answer trivia to remove all of their confusions passionately. Their course and curriculum are very much well updated to make them industry-ready . Moreover thd college management is very much sincere about their guidance to their students, so they conduct different types of workshops, training programs, seminars, entrepreneurship etc organised by renowned National and International companies.
Placements: The average salary offered is Rs.13.8 Lac per annum. The highest package was Rs.1.39 crores offered by Microsoft. And the average placement percentage is about 85%.

Top Recruiters: Accenture, Adobe, Amazon.com (http://Amazon.com) ,  Cadbury, TCS, Citigroup, 3M,  Infosys,  John Deere, Microsoft,  MU Sigma, Nvidia Corporation, Morgan Stanley,  Barclays Bank, ONGC, Oracle Financial, Qualcomm, TATA, ITC, Eaton Ltd
3. IIT DELHI:
Academics: IIT Delhi offers Bachelor of technology programs in several fields as well as dual degree B.Tech-cum-M.Tech programs. Also it distinguishes itself from other IIT institute with their latest and unconventional courses and several innovative researches. The ample and sophisticated manner and impressive teaching style of their faculties amuses every student in their campus.
Placement record: Microsoft offered an overwhelming package of Rs.1.4 CR which is the highest package till now. Their average salary is 13.5 lakhs per annum. IIT Delhi has almost 82% placement records every year; however one thing must be remarkable specially for CSE and ECE students is that it has 99% placement records in both of the streams.
Top Recruiters: Amazon, Cisco, Microsoft, Accenture, IBM, Nvidia Graphics, ICICI Bank, Nestle India, Infosys, Blue Star Limited, Yahoo, Deloitte, Dell

4. IIT KHARAGPUR:
Academics: IIT-KGP, the largest and oldest IIT, offers worldwide recognition to every student through the field of academics and research and also in entrepreneurship and best placement. They empower every student to do innovative research projects by implementing their own imaginatination and logic under the supervision of several renowned international industries. There are almost 700 eminent faculties who've completed Ph.D from the Internationally renownded universities and done commendable researchs and consultancy projects funded by National and International agencies and corporate sector.
Placements: The average salary offered during campus-placement is Rs.13.3.Lacs per annum and average placement percentage is about 80% combining all streams.

Top Recruiters: Flipkart,  Intel, Apple,  Goldman Sach,  IBM Research, Google, JP Morgan, Microsoft, Uber,  American Express, Airbus, Reliance Jio,  HSBC Global, Synopsys.

You can also go through the full details of the topmost IITs from the following Careers360 website:

https://engineering.careers360.com/colleges/list-of-top-iit-colleges-in-india You can also check your admission possibilities in your desirable institutions through the link provided below:

https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer

Hope this informations are more than sufficient for you.

Wish you all the best.