Everyone except nationals of Bhutan, Maldives and Nepal needs a visa to visit India.
Most nationalities can obtain an e-visa. E-visas are valid for six months from the date of issue, and cost around US$50. Processing takes from one day to one week.
A visa on arrival is available for tourists from Japan, South Korea and UAE. The on arrival visa is only available at Bangalore, Chennai, Delhi, Hyderabad, Kolkata and Mumbai airports for a fee of US$60. The visa is single entry and only valid for 30 days.
Everyone else will need to head to an embassy or consulate and wait.
If you would like to stay in India for longer than six months, you will need to leave the country and apply for another visa. Getting another visa after you have had two in a row may prove difficult.
Visa on arrival details
Indian visa online application - Evisa
Indian Embassies and consulates