India started voting on Thursday to elect members to the lower house of Parliament.
Prime Minister Narendra Modi and his ruling Bharatiya Janata Party hope to win power for a second five-year term — but opinion polls suggest it could be a close fight to the finish.
The coalition led by Modi's party is predicted to win 273 of the 543 parliament seats being contested, one seat more than the number needed to govern, Reuters reported.
There'll be around 900 million eligible voters in India, almost three times the size of the U.S. population. That makes the elections — spread over seven phases that end on May 19 — the largest democratic exercise in the world. Indian citizens who are 18 or older are eligible to participate.
Votes will be counted on May 23 and results are likely to be announced the same day.
India follows the parliamentary system of government where the lower house — known as the Lok Sabha — comprises elected representatives. There are a total of 545 seats, two of which are nominated by the president, while the rest are contested.
The party that wins the majority of seats in the lower house will form a government.
If no party wins a clear majority, coalitions will have to be formed. At the moment, there are two major coalitions: The National Democratic Alliance is led by Modi's BJP and makes up the current government; while the United Progressive Alliance is led by the Indian National Congress.
Analysts have previously said that the emergence of a so-called "third-front government" — where neither the BJP nor Congress holds a major sway — could potentially spook markets and dent investor confidence in India.
Since 2014, the BJP-led National Democratic Alliance (NDA) has governed India. During that time, Modi introduced a number of prominent economic reforms such as the implementation of the goods and services tax, as well as demonetization — where all 500 and 1,000 rupee banknotes were unexpectedly withdrawn and new 500 and 2,000 rupee denomination notes issued.
While growth ticked up under his government, not everyone benefited equally — something that had been a major promise during his 2014 campaign.
The main challenger to Modi is Rahul Gandhi, the president of opposition party Congress.
He is a member of India's most influential political dynasty: his father, Rajiv Gandhi, and grandmother, Indira Gandhi, were former prime ministers. His great-grandfather, Jawaharlal Nehru, was India's founding prime minister.
In the last election, Congress had won just 44 seats in the lower house. Since then, the party has been on the upswing and recently won three major state elections.
Analysts broadly expect Modi to return for a second five-year term as prime minister. But some have said that the BJP may lose its single party majority in the lower house and the NDA coalition may need the support of additional parties.
Political consultancy Eurasia Group said earlier this month they predict Congress holds only a 15 percent chance of returning to power.
While BJP and Congress are the only two parties with a pan-Indian presence, voters in a number of states in India are expected to favor regional parties.
Among India's 29 states and seven union territories, Uttar Pradesh is the most populous, with more than 200 million people. The state elects 80 members to the lower house and doing well there is crucial for any party to get ahead in the polls. In the last election, the BJP and its ally won 73 out of the 80 seats in Uttar Pradesh.
Several local parties have formed an alliance to counter Modi's party, making it tough for the BJP to repeat its performance in the 2019 elections.
Other areas that will be closely watched include the western state of Maharashtra, with 48 lower house seats; West Bengal in the east, with 42; Bihar, in the north, with 40; and Tamil Nadu, in the south, with 39.
Jobs: One of the pressing issues during Modi's five-year tenure was lackluster job creation, despite strong economic growth. The Centre for Monitoring Indian Economy think tank estimated that around 11 million jobs were likely lost in 2018.
In a survey of more than 273,000 people, the election watchdog Association for Democratic Reforms found that better employment opportunities was the top priority for voters.
Both the BJP and Congress, in their respective election manifestos, promised to create new job opportunities in the country.
Security: In February, tensions between India and Pakistan escalated after military planes from both sides carried out tit-for-tat air strikes in each other's territories, and their troops traded fire along the de facto border in Kashmir. Analysts have said the skirmish boosted support for Modi and the BJP as security concerns overtook economic worries.
"Dismal showing at the state elections last year left little doubt that the BJP had lost significant grip on government," Vishnu Varathan, head of economics and strategy at Mizuho Bank, wrote in a note. "Since India-Pakistan tensions flared in February this year, support for the BJP (NDA) has rebounded."
"This has handed the BJP the gift of nationalist and national security planks on which the BJP is able to boost support standings," he added.
In its election manifesto, the BJP said it would strip special rights and privileges from permanent residents in India's Muslim-majority state, Jammu and Kashmir, which could potentially invite a backlash.
Farmers: India's farmers, who make up a sizable portion of the workforce, have struggled for years due to low crop prices, rising costs, demonetization and widespread drought.
Both parties have outlined potential policies designed to boost wages for farmers.
BJP, for its part, says it plans to launch a pension scheme for small and marginal farmers to provide them with social security in old age. Modi has also pledged to spend 25 trillion rupees (around $359 billion) in farm and rural productivity. In the February budget, the BJP announced that farmers who own up to 5 acres of land will receive 6,000 rupees in income support each year. That policy will be extended to all farmers, according to the party's election manifesto.
In a political blow to Modi, the BJP lost elections in three important rural states last year.
Congress has also outlined a number of schemes to help farmers including expanding an existing jobs program to guarantee 150 days of employment in a year and to write off farm loans. The party also has an ambitious pitch to alleviate poverty in India by handing out about $1,000 per year to the bottom 20 percent of households. The plan has drawn skepticism from economists who questioned how the program will be funded and who would be eligible for it.
— Reuters contributed to this report.