Indians are voting in the seventh and final phase of national elections, wrapping up a six-week-long campaign season with Prime Minister Narendra Modi's Hindu nationalist Bharatiya Janata Party (BJP) seeking re-election for another five years.
Nearly a 100 million people are eligible to vote on Sunday in 59 constituencies across seven states - including the politically-critical Uttar Pradesh in the north and West Bengal in the east.
Sunday's voting also covers Modi's constituency of Varanasi, a temple town where he was elected in 2014. He spent Saturday night at Kedarnath, a temple of Hindu god Shiva nestled in the Himalayas in northern India.
Counting of votes is scheduled for May 23.
The election is seen as a referendum on Modi's five-year rule. He has adopted a nationalist pitch in trying to win votes from the country's Hindu majority by projecting a tough stance against Pakistan, India's Muslim-majority neighbour and archrival.
Modi has played up the threat of Pakistan, especially after the suicide bombing of a paramilitary convoy on February 14 that killed 40 Indian soldiers.
Reporting from Varanasi, Al Jazeera's Sohail Rahman said while the BJP positioned national security as its main poll agenda, the opposition attempted to corner Modi by focusing on issues of development.
"Discourse certainly changed after Pulwama attacks and national security became the issue. However, people and experts that I talked to said actual issues haven't come out, issues like health, education, sanitation and infrastructure, which the opposition used to target the government."
"The incumbent BJP government has been very reluctant to talk about what they have achieved in the last five years," he said.
The Congress and other opposition parties are challenging Modi over a high unemployment rate of 6.1 percent and farmers' distress aggravated by low crop prices.
Some of Modi's boldest policy steps, such as the demonetisation of high currency notes to curb black-market money and bring a large number of people into the tax net, proved to be economically damaging.
A haphazard implementation of "one nation, one tax" - the Goods and Services Tax - also hit small and medium businesses.
Voter turnout in the first six rounds was approximately 66 percent, the Election Commission said, up from 58 percent in the last national vote in 2014.
The election has taken place in a charged atmosphere as Modi's BJP sought a second term by pushing policies that some say have increased religious tensions and undermined multiculturalism.
The campaigning has been marred by accusations and insults, as well as the unprecedented use of social media.
Voting has largely been peaceful but for sporadic violence in the eastern state of West Bengal, where the BJP is trying to wrest seats from the Trinamool Congress, a powerful regional party that is currently governing the state.
In a drastic and unprecedented action, the Election Commission cut off campaigning early in West Bengal on Thursday after days of clashes in the final stretch of the election.
Pre-election poll surveys by the media indicate that no party is likely to win anything close to a majority in parliament with 543 seats. The BJP, which won a majority of 282 seats in 2014, may need some regional parties as allies to stay in power.
A Congress-led government will require a major electoral upset.