Diploma

1)
To become a commercial pilot :
* You need to first possess a Student Pilot License. You must be over 17 years of age and have completed 12th in Science (Physics and Mathematics) with 50%.
* Your vision in one eye must be perfect. In general medical terminology, it is called 6/6 eyesight. In the other eye, you could have an imperfection of 6/9, which must be correctable to 6/6.
General physical fitness is mandatory. You must be free of any disease that can hamper normal function.
* You need to register at a flying club which is recognized by Directorate General of Civil Aviation (DGCA), Government of India.
* Next is Private Pilot License which includes sixty hours of flying. A Commercial Pilot Licence may be obtained only after a PPL and 250 hours of flying.
2)
Some of the institutes offering commercial pilot training are :
-Academy of Carver Aviation Private Limited, Pune
-All India Institute of Aeronautics, Dehradun
-Center for Civil Aviation Training (CCAT), Delhi
-Glorietta Aviation, Ghaziabad
-Fly wings Aviation PVT. LTD., Mumbai
For more, you may refer to the link mentioned below.
https://hospitality.shiksha.com/commercial-pilot-training-in-india-categorypage-6-87-301-0-0-1-1-2-0-none-1-0#page-top
While selecting the best institute, you need to check some of the important parameters such as recognition, year of establishment, batch size, syllabus, faculty, fees, placements etc.

HK Yadav, One of the fastest growing industries, India is the 7th largest producer in the world with an average annual production of 17.5 million vehicles. This sector contributes 7% of the country's GDP by volume. According to a report of Society of Indian Automobile Manufacturer (SIAM) 2015, our country is also the 4th largest automotive market by mass.
According to industry estimates, automobile sector is expected to sell more than 6 million vehicles by 2020. The latest report by SIAM also says that in April-March 2015, overall automobile exports grew by 14.89% over the same period last year.
Looking at this data, it is clear that India is a potential engineering automobile market and jobs in this sector is expected to grow significantly.
Automobile Engineering is a branch of engineering that deals with designing, manufacturing and operating automobiles. It incorporate elements of mechanical, electrical, software and safety engineering as applied to design and manufacture buses, bikes, trucks and other vehicles and machines.
The course in Automobile Engineering deals with the creation and maintenance of automobiles, starting from designing the vehicles to manufacturing components, assembling and testing them for safety.
Automobile Engineers are demanded in both India and abroad. As it's a huge industry, there are great employment opportunities in Private National and Multinational Automobile companies, Service Stations, Private Transport companies, Defense Services and Self Employment by setting up Automobile Garage or Maintenance Workshop.
Many good universities are offering courses in Automobile engineering. They offer world class environment to their students along with good placements. Some even offer good scholarships to students.
Check their websites or call their toll free no.s.
Good luck.