Travelling to India to attend the 36th International Geological Congress, may require you to procure a Visa or an eVisa.
Foreign citizens possessing an Overseas Citizen of India (OCI) registration certificate or holders of a Persons of Indian Origin (PIO) Card are exempt from visa requirements, have the right of domicile in India and are allowed unlimited entries into India.
Citizens of Bhutan and Nepal do not need a Visa to visit India (unless arriving from Mainland China).
Citizens of Maldives do not require visas to enter India for up to 90 days (unless arriving from Mainland China).
For citizens of all other countries, there is a requirement to apply for, and be granted a visa by the Indian High Commission, before performing a journey to India.
Depending on your country of Citizenship, you would need to procure an eVisa or a Visa issued by the Indian Consulate nearest to you.
The procedure to apply for an Indian visa varies depending on your country of citizenship.
The Indian government offers an eVisa facility to citizens of select countries.
Below is a link to check eligibility and the process for application of an eVisa to visit India.
In case your country of citizenship is not a part of the list mentioned in the link, you would need to apply for a Visa at the Indian embassy / consulate closest to you.
Please find the Ministry of External Affairs link with more information -