India’s Election Commission announced on Sunday that the upcoming national election will be held in seven phases in April and May, as Prime Minister Narendra Modi’s Hindu nationalist party seeks a second term.

About 900 million people are eligible to vote in a staggered process that allows the government to deploy tens of thousands of troops to prevent outbreaks of violence and the capture of voting stations by party activists.

Chief election commissioner Sunil Arora said the election will be held April 11, 18, 23 and 29, and May 6, 12 and 19. The votes will be counted May 23.

Modi’s Bhartiya Janata Party, or BJP, hopes the government’s recent tough stand against Pakistan will help it retain its popularity despite suffering a setback in December when it lost three key state elections to the opposition Congress party.

The Indian premier tweeted shortly after the electoral commission's announcement, urging people to come out in droves to vote.

"The festival of democracy, Elections are here. I urge my fellow Indians to enrich the 2019 Lok Sabha elections with their active participation. I hope this election witnesses a historic turnout. I particularly call upon first time voters to vote in record numbers," he wrote.

On Saturday, the Election Commission ordered political parties to tell their candidates and leaders not to display photographs of defense personnel in advertisements as part of their election campaigns.

The order came after billboards featuring the BJP, including Modi and the party’s president, Amit Shah, along with air force pilot Abhinandan — who was captured by Pakistan last month after his plane was shot down — appeared in parts of the country.

“The Ministry of Defence has brought to the notice of the Commission that photographs of the Defence personnel are being used by the political parties, their leaders and candidates in advertisements as part of their election propaganda and requested the Commission to issue suitable instruction in this regard,” the advisory by India's Election Commission reads.

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The commission said armed forces are “apolitical and neutral stakeholders in a modern democracy”. "It is, therefore, necessary that political parties and leaders exercise great caution while making any reference to the Armed Forces in their political campaigns.”

Leading contenders

Modi's BJP and the left-leaning Congress led by Rahul Gandhi — the latest scion of the Gandhi-Nehru dynasty — are the two strongest challengers among hundreds of political parties from across the culturally and geographically diverse country.

Modi, whose right-wing party won an outright majority in the 2014 elections, enters the race in a strong position, the 68-year-old remaining a popular figure and the BJP a well-oiled political machine.

In recent weeks he has been able to bolster his nationalist credentials in India's most serious standoff with Pakistan in years, sparked by a suicide bombing in Indian-occupied Kashmir's Pulwama on February 14 that killed 40 Indian paramilitaries.

Twelve days later, the Indian air force bombed what New Delhi said was a training camp of a militant group deep inside Pakistan. Doubts, however, have been raised about what the raid achieved.

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When Pakistan carried out its own air raid a day later, a dogfight ensued and an Indian aircraft was shot down and its pilot captured by Pakistan. The pilot was freed as a gesture of peace by Pakistan.

While Modi and BJP leaders have been projecting the party and its leaders as decisive and tough on national security, opposition parties have accused them of using national security matters to try to influence voters.

Modi, shrugging this off, has continued to talk tough, accusing the opposition of being weak.

“We won't spare anybody who is looking to destroy our country even if their (terrorists') chiefs are sitting on the other side of the border,” Modi claimed during a recent rally.

“But the oppositions have a problem with such stern actions too. But I am going ahead with my resolve to root out terrorism,” he said in his home state of Gujarat.

Gandhi's turn?

The prime minister has also sought to contrast his humble origins as a tea seller against Gandhi, the 48-year-old privileged half-Italian princeling of India's most famous family.

But opinion polls have suggested ebbing support for the BJP, and even that it may fall short of the 272 seats it needs to form a government on its own.

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Gandhi, long criticised as a lacklustre leader, has also started looking more recently like a serious challenger.

Congress, which has ruled India for much of its time since independence from Britain in 1947, won three key state election victories in December, chipping into Modi's core support base in the Hindi “Cow Belt” regions home to nearly half a billion voters.

He has also gone on the offensive over Modi's economic record, with the Congress state wins attributed to the prime minister's perceived failure to help impoverished farmers and to create enough jobs.