Diploma

For admission in Polytechnic course after 12th (Science) you need to crack an entrance examination called Diploma entrance test, otherwise can join any private institution that perform their own Diploma qualification test. After joining there is a branch selection in which you have to a specific branch like mechanical. Following are some top colleges where you can apply:
All India Shri Shivaji Memorial Society Polytechnic
Anjuman Polytechnic
Bhandara Polytechnic
Acharya Shriman Arayan Tantra Sansthan
Amrutvahini Polytechnic
Guru Nanak Dev Polytechnic
Meera Bai Polytechnic
Tool Room & Training Centre
Arya Bhatt Polytechnic
Gobind Ballabh Pant
Kasturba Polytechnic for Women
Aryabhatt Polytechnic.

There are lots of different fields and courses for build a career after 12th but according to my experience lots of career scope in animation and VFX field. Animation and VFX is the biggest part of Media and Entertainment industry. Accordingly FICCI report Media and Entertainment Industry is highly growth field right now. The Federation of Indian Chambers of Commerce and Industry (FICCI) is an association of business organizations in India. The media and entertainment industry in India consists of many different segments under its folds such as television, print, and films, radio, music, OOH, animation, gaming and visual effects (VFX) and Internet advertising. You can work all these segments. In these segments you need just understanding of software skill, tools of the industry no further required. As per the combined survey report by KMPG and FICCI, the entertainment industry in India is expected to expand by 12.5% every year and is likely to reach US$20.09 billion by the year 2013. The industry is estimated to achieve growth of 13 per cent in 2011 to touch US$16.2 billion. As the industry braces for exciting times ahead, the sector is projected to grow at a CAGR of 19 percent 2020 which is the highest growth as compare to other fields, that means more income and jobs. In MNCs like Pixar, Technicolour (Bangalore), Rythm and Hues (Hyderabad), Red chilies, Prime Focus, DQ entertainment etc. Salaries are more than software engineers. There are many colleges and institutions for Animation in India. If you want to really choose right place for this filed, focus on just few things. These things are Mentors (faculty members), Course content, Career Opportunities (Placement), Environment and Equipment's (Labs). Only these things can make a brand and in India there are just few brand institutes who provide a quality education in Animation field. For your more information please visit:
https://www.shiksha.com/college/maac-Chandigarh-37864
You can also consider any of these following India's best Institution.