Excerpted from the India Career Guide
Applying for visas and work permits to study, work or travel in India is not complicated, but a visa application requires adequate supporting documentation. Indian immigration laws require foreign nationals to apply for visas depending on the category most suited to the purpose of the visit. As the type of the visa cannot be changed once the foreign national arrives in India, the applicant should verify the suitability of the visa category. An applicant is encouraged to apply as soon as possible and to contact the embassy or consulate responsible for the applicant’s place of residence to find specific requirements and the application process for the visa. Applicants are also encouraged to visit the Indian Bureau of Immigration website. Both multiple- and single-entry visas are available.
Employment visas are granted to highly skilled and/or qualified professionals who have been employed by an employer in India. The visa will not be issued if qualified Indians are available or for routine, ordinary, secretarial or clerical jobs.
All employment visa applications must be sponsored by an entity in India. Employment visas are also granted to those who are employees of Indian companies or perform honorary work (without salary) with registered NGOs in India. Foreign employees who have been granted visas to work with a particular employer cannot take up employment with another employer in India. To do so, they would need to obtain new visas.
Student visas are issued to students to enable them to pursue studies at recognized educational institutions in India for the duration of the academic course of study or for a period of five years, whichever is less, on the basis of letters confirming admission of the applicant and the duration of the course of study.
A letter confirming admission from the Indian educational institution along with evidence of financial arrangements to stay in India should accompany the application. In case of admission to medical or paramedical courses in India, a letter of approval or a No Objection Certificate from the Ministry of Health, Government of India, is also required. Similarly, for admission to graduate or post-graduate courses in engineering/technical institutions in India, a letter of approval or a No Objection Certificate from the Ministry of Human Resources Development (Department of Education) is required.
A Business Visa (BV) is granted to those individuals who wish to visit India for business and trade purposes. A letter from the applicant’s company/organization in his/her country as well as an invitation letter from an Indian business/organization indicating the nature of the applicant’s business, the probable duration of his/her stay, and the places and firms to be visited in India is required.
Applicants sending their documents by mail/courier are requested to ensure their applications are complete and meet all requirements. An applicant's financial background and expertise in the field of intended business are checked prior to granting a business visa. The consular post will also check the documentary proof of company registration or registration with an institute like the State Industries Department or the Export Promotional Council.
This is just a short sample of what you’ll find in over 100 pages of information in the complete India Guide.