First what’s your nationality ? According to this it may help you to consider working in an Indian company or in a western one.
Else you can still search the Internet about the domain you want to work in, and to search for the biggest company is those fields.
Websites like Linkedin can help you discover a new network of people or groups of people working in India that can help you.
Do you know someone working in a worldwide company somewhere else than India ? It can be a first step to get in touch with people you know in companies abroad, since there are good chance the company get a smaller one or a part of its production chain or whatever in India.