https://indianvisaonline.gov.in

A valid passport and visa are required for travel to India. The Indian government now offers two options for tourists, a traditional tourist visa or an e-Tourist Visa (eTV) issued electronically.

A traditional Indian tourist visa is stamped inside the traveler’s passport. The visa application process requires the original passport and original signed application form along with all required supporting documents. It is recommended for all travellers to apply for the traditional Indian visa to be stamped inside the passport to avoid possible delays or difficulties upon arrival in India.

e-Tourist Visa(eTV):
https://indianvisaonline.gov.in/visa/tvoa.html

The India ETA allows one single entry for a stay of up to 30 days in India. A maximum of two ETA visas can be issued within one year. A traditional Indian visa allows multiple visits to India and is generally valid for a stay of up to 90 days.

The India e-Tourist visa allows for visa on arrival issuance only for arrival and departure from the airports in Ahmedabad, Amritsar, Bengaluru (Bangalore), Chennai, Cochin, Delhi, Gaya, Goa, Hyderabad, Jaipur, Kolkata, Lucknow, Mumbai, Tiruchirapalli, Trivandrum & Varanasi. If arriving or departing from any other port of entry, please apply for a traditional Indian visa.

The Indian e-Tourist Visa (eTV) is issued and stored electronically. The traveler will not receive any document in the mail. You will be sent the approved e-Visa via email. This must be printed and carried with you and your valid passport upon entry to India. The visa on arrival will be stamped in India after biometric information is taken at the airport.

India Visa Valid

It is issued for a single entry for a stay in India for up to 30 days from the date of arrival.

The Indian ETA cannot be extended or converted for any other purpose, and is not valid for travel to restricted areas. A maximum of two ETA visas can be issued within a 12 month period.

Travellers who would like a longer visa validity or multiple entries, or who wish to avoid delays at the airport in India, should apply for a traditional visa.
Citizens of Australia, UK, Belgium, France, Switzerland, Italy can get information from: http://www.vfsglobal.com
Citizens of the United States can check for visa from: Travisa 
Citizens of Germany can check for visa from: IVS Global 
Citizens of Austria can check for visa from: BLS Austria
Citizens of Canada can check for visa from: BLS Canada