Passport
You must have a passport with you all the time. It's the most basic travel document. Also ensure that your passport will be valid for the entire period you intend to remain overseas, if your passport is lost or stolen, immediately contact your country's embassy or consulate in India and also to nearest police station.

Apply for Passport
The best time to apply for a passport or to renew is during the fall and winter. Before any trip, be sure to check your passport's expiration date and, if necessary, renew it as soon as possible.

Visa
You need a visa to visit India. But if you are coming from Nepal you only need Identification, and visa is issued at the airport only. Note that with a three month visa, your entry to India must be within 30 day's from the date of issue of the visa. Also, the six month visa is valid from the date of issue of the visa, not the date you enter India five month after the visa was issued, it will be valid only for one month not the full six month. If you enter India the day after it was issued, you can stay for the full six month.

General Regulations for applying for Visa
Passport valid for a minimum of six months beyond the date of intended departure from India should accompany visa applications.

Paste one photo and staple the other one on the form at specified place.

Foreigners holding other nationalities (other than the country where applying for visa), should submit proof of long-term (at least three years)/ permanent residence in the country (where applying). For citizen of other countries, reference has to be made to their country of residence for which an additional fee is applicable and will involve extra processing time. Please refrain from making inquiries about the status of application during this time.

Tourist Visa
Is given for 6 months normally, rest specifically depends on the country of residence. The applicant is required to produce/submit documents in proof of his financial standing. Tourist travelling in groups of not less than four members under the auspices of a recognised travel agency may be considered for grant of collective tourist visa.

Business Visa
Valid for one or more year with multiple entries. A letter from sponsoring organization indicating nature of business, probable duration of stay, places and organizations to be visited incorporating there in a guarantee to meet maintenance expenses, etc. should accompany the application.

Student Visa
Are issued for the duration of the academic course of study or for a period of five years whichever is less, on the basis of firm letters of admission from Universities/recognized colleges or educational institutions in India. Change of purpose and institutions are not permissible.

Transit Visa
Are issued for a maximum period of 15-days with single/double entry facilities to bonafide transit passengers only.

Journalist Visa
Are issued to professional journalists and photographers for visiting India. The applicants are required to contact on arrival in New Delhi, the External Publicity Division of the Ministry of External Affairs and in other places, the Office of the Government of India's Press Information Bureaus.

Conference Visa
Are issued for attending conferences/seminars/meetings in India. A letter of invitation from the organizer of the conference is to be submitted along with the visa application. Delegates coming to attend conferences may combine tourism with attending conferences

General Visa Information

Duration
Depends on the type of visa applied.

Fees
The fee structure depends on the nationality of the passport holder and type/duration of visa applied. The existing fee structure is:
Transit Visa 5 $
Visas with validity upto six months 30 $
Visas with validity upto one year 50 $
Student Visa 50 $
Visas with validity between one to five years 100 $

Visa fees indicated in US$ are payable in local currencies as well. Visa fees are not refundable except in cases where a visa already issued is cancelled thereafter.
These are indicative prices, please confirm with the Local Indian Embassy

Tax Clearance Certificates
If you stay in India for more than 120 days you need a 'tax clearance certificate' to leave the country. This supposedly proves that your time in India was financed with your own money, not by working in India or by selling thing or playing black market.
Basically all you have to do is find the Foreign Section of the Income Tax Department and turn up with your passport, visa extension form, any other similar paperwork and a handful of bank exchange receipts (to show you really have been changing foreign currency into rupees officially). You fill in a form and wait for anything from 10 minutes to a couple of hours; you are then given your tax clearance certificate.

Photocopies
Keep photocopies of your important travel documents, which obviously should be kept separate from the originals in the event that these are lost or stolen.

Take a photocopy of the first page of your passport (with personal detail and photograph), as well as a copy of the page with your Indian Visa, a photocopy of your travel insurance policy, and keep a record of the traveller's cheques you have exchanged, where they were encashed, the amount and serial number. Encashment receipts should also be kept separate from your airlines tickets and your credit card; it's not a bad idea to leave photocopies of your important travel documents with a friend or relative at home.