Not being from India, it would be hard for me to give you particulars, but I can give you some ideas for how to find out. I know India has been looking at cloud seeding for about 60 years, and several state governments have tried it out. Where you'll want to start, then, is finding out how those governments actually set up the projects. Then look to see what the rules are for setting up a small business of your own. Then start looking at costs and create a budget. Meanwhile, you're gathering support from others—people who want to work with you to create the business in some way.
In the United States we would write a business plan—how, exactly, we're going to start the business, what it will do, what equipment is needed and how we'll get it, who we'll work with, etc. You may have to get a license . . . but those details are for you to figure out because it will be different in India.
Here is an article about a couple of states in India that have recently carried out cloud seeding projects. Find someone to talk to from each of those state governments who were involved in the project and ask how they did it. Talk to the pilots of the planes and ask them how it went. Find out where they got their supplies. This will give you a start.