All foreign nationals entering India are required to possess a valid international travel document in the form of a national passport with a valid visa obtained from an Indian Mission or Post abroad.

All Individual visa seekers are requested to apply for the Indian Visa through Online application link.

The duly signed physical copy of the application form completed in all respect and submitted successfully, is to be submitted at the concerned Indian Visa Application Center (IVAC) or directly to Indian Mission/ Post, on the scheduled date of interview along with the requisite supporting documents.

There are several types of visa, including Business Visas, Tourist Visa on arrival and Conference visa.
Option 1 – Business Visa
You will need to submit the visa application yourself to an Indian consulate in your country along with the letter of invitation and letter of incorporation or certificate of registration of host organization.

Validity of visa:  Business visas may be valid upto six months/one year or more with multiple entries.

Expected time duration for processing the application: 4-5 working days

Support documents for the visa application includes:
Letter of invitation (which you will receive on completing your registration at the on-line portal and the payment); Certificate of registration of the host organization (please write to to request for the certificate of registration of TIFR).
Option 2 - Tourist Visa on Arrival for casual business visit.
The Indian Government also offers an option to get your Tourist Visa on Arrival (TVoA) for casual business visit. Please visit their website to know more and submit your online application for electronic travel authorization (ETA) approval. Instructions for applicants applying for the TVoA are available here, please go through them carefully.

For further assistance, please write to us at icts-ten @ icts . res . in
Vaccination certificates:

Participants (foreigners or Indians) from yellow fever endemic countries need to produce vaccination certificate of yellow fever at the immigration desk at the Indian airport.

The following countries are regarded as yellow fever endemic :

Angola, Benin, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Congo, Cote d' Ivoire, Democratic Republic of Congo, Equatorial Guinea, Ethiopia, Gabon, Gambia, Ghana, Guinea, Guinea Bissau,  Kenya, Liberia, Mali, Mauritania, Niger, Nigeria, Rwanda, Senegal, Sierra Leone, Sudan, South Sudan,Togo, Uganda.

South America:
Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guyana, Guyana, Suriname, Trinidad (Trinidad only), Venezuela, Panama, Paraguay, Peru. 
Oral polio vaccine is mandatory for all the persons travelling to India from Afghanistan, Equitorial Guinea, Ethiopia, Iraq, Israel, Nigeria, Somalia, Cameroon, Pakistan, and Syria.

The medicines should be administered 4 weeks prior to your travel to India through a Government approved medical clinic, Institute or hospital in your country.  The certificate of Polio Vaccination should be carried along with the other immigration documents. This is a mandatory requirement as per the Government of India.

Source: Airport Health Organization, Bangalore and World Health Organization