Voting in a six-week election that is a referendum on Narendra Modi, the populist prime minister who is running for an uncommon third term as the nation's leader and has championed an assertive brand of Hindu nationalist politics, began for millions of Indians on Friday.
In the first 21 states to hold elections, from the tropical Andaman Islands to the Himalayan Himalayas, voters started forming lines at polling places hours before they were permitted inside at 7am, according to the Associated Press.
The staggered elections, which take place until June 1, will see almost 970 million people, or more than 10% of the world's population, choose 543 members to the lower house of parliament for a five-year term. On June 4, the votes will be tallied.
This election, which is anticipated to be among the most important in Indian history, will put Modi's hold on power to the test.
After Jawaharlal Nehru, the nation's first prime minister, Modi would be the only other Indian leader to hold the position for three terms.
With the Indian National Congress and other strong regional parties leading a large opposition alliance, most polls indicate that Modi and his Hindu nationalist Bharatiya Janata Party (BJP) will prevail.