Prime Minister Narendra Modi was widely tipped to win India's election on Tuesday, in what would be a triumph for his Hindu nationalist drive that has thrown the opposition into disarray and deepened concerns for minority rights.
Exit polls have shown 73-year-old Modi well on track for victory after a six-week-long election that saw 642 million people vote in seven stages in the world's most populous country.
Modi said at the weekend he was confident that "the people of India have voted in record numbers" to re-elect his government, a decade after he first became prime minister.
Observers believe his appeals to growing Hindu nationalist sentiment will give him a third term in power.
Modi's opponents have struggled to counter the campaign juggernaut of his Bharatiya Janata Party (BJP), and been hamstrung by infighting and what they say are politically motivated criminal cases aimed at hobbling challengers.
US think tank Freedom House said this year that the BJP had "increasingly used government institutions to target political opponents".
On Sunday, Arvind Kejriwal, chief minister of the capital Delhi and a key leader in an alliance formed to compete against Modi, returned to jail.
Kejriwal, 55, was detained in March over a long-running corruption probe, but was later released and allowed to campaign as long as he returned to custody once voting ended.
"When power becomes dictatorship, then jail becomes a responsibility," Kejriwal said before surrendering himself, vowing to continue "fighting" from behind bars.
In the lead-up to the election, many of the 200 million-plus Muslim minority grew increasingly uneasy about their futures and their community's place in the nominally secular country.
Modi himself made a number of strident comments about Muslims on the campaign trail, referring to them as "infiltrators".
The polls were staggering in their size and logistical complexity, with voters casting their ballots in megacities New Delhi and Mumbai, as well as in sparsely populated forest areas and in the high-altitude territory of Kashmir.
Votes were cast on electronic voting machines, so the tally will likely be rapid, with results expected within hours.
Counting will begin at 8:00 am (0230 GMT) in key centres in each state, with the data fed into computers.
"People should know about the strength of Indian democracy", chief election commissioner Rajiv Kumar said Monday, vowing there was a "robust counting process in place".
India's major TV networks will have reporters outside each counting centre, competing to flash results for each of the 543 elected seats in the lower house of parliament.
In past years, key trends have been clear by mid-afternoon with losers conceding defeat, even though full and final results may only come late on Tuesday night.
Celebrations are expected at the headquarters of Modi's BJP if the results reflect exit poll predictions.
The winning post is a simple majority of 272 seats, and the BJP won 303 at the last polls in 2019.
Election chief Kumar on Monday proclaimed the 642 million votes cast a "world record".
But based on the commission's figure of an electorate of 968 million, turnout came to 66.3 percent, down roughly one percentage point from 67.4 percent in the last polls in 2019.
Final voter data is yet to be released as repolling took place in two stations in West Bengal state on Monday.
Analysts have partly blamed the lower turnout on a searing heatwave across northern India with temperatures in excess of 45 degrees Celsius (113 degrees Fahrenheit).
At least 33 polling staff died from heatstroke on Saturday in Uttar Pradesh state alone, where temperatures hit 46.9C (116.4F).
Polling should have been scheduled to end a month earlier, Kumar acknowledged. "We should not have done it in so much heat", he said.
