Visas
Six month multiple-entry visas are now issued to most nationals regardless of whether you intend staying that long or re-entering the country. Only six-month tourist visas are extendable. Most Indian embassies and consulates won't issue a visa to enter India unless you hold an onward ticket. Be careful to check whether your visa is valid from the date of entry or the date of issue.

TYPES OF VISAS:
Tourist Visa:Is issued for 6 months, 1 year and 10 years. The period of stay in India (for each visit) is 6 months only.
Entry Visa :Entry visas are issued only to people of Indian origin. Such visas are valid for 6 months, 1 year or 5 years.
Business Visa :i)Valid for 6 months/one year with multiple entries. A letter (on company letterhead) from Sponsoring Organization indicating the nature of applicant's business, probable duration of stay, places and organizations to be visited incorporating therein a guarantee to meet maintenance expenses, etc. should accompany the application. ii) Long term Business visas for ten years (multiple entries) in case of US Citizens and five years (multiple entries) for other nationals are available only to those who have set up industrial/business joint ventures in India. This fact, along with the details of joint venture in India must be mentioned in the sponsorship letter.
Student Visa :Valid for six months to one year with multiple entries for bona fide students to pursue regular studies at recognized institutions in India.
Transit Visa(IN PERSON ONLY):Valid for single/double entry for maximum stay of 15 days for bona fide transit purposes only.
Missionaries:Valid for single entry and duration as permitted by Government of India. A letter, in triplicate, from sponsoring organization indicating intended destination in India, probable length of stay, and nature of duties to be discharged should be submitted along with guarantee for applicant’s maintenance while in India. NOTE: Processing of applications for research and missionaries may take up to three months.
Journalist visa -Journalist visas are issued to professional journalists and photographers for a maximum of three months only. “Journalists, who are not accredited to India, irrespective of their origin, are given only 3 months single entry visa, irrespective of their origin. Accordingly, journalists who wish to visit India for tourism/ sightseeing or any other purpose are advised to apply for 3 months visa only. Please note that it will not be possible to refund the excess fees in case a journalist applies for a long-term visa .”
Conference visa- Conference visas are issued for a period of 1 month, or for the duration of the conference only. A letter of invitation from the organizer of the conference is to be submitted along with the visa application.
Transfer of Valid visa -Valid visa can either be transferred from the expired passport to the new passport by submitting the visa application form, both the passports and required fee (see below) OR the passport holder could travel with both the expired passport containing the valid visa and the new passport keeping them together.