India's 2024 general election - to be held over six weeks between 19 April and 1 June - will be the biggest the world has ever seen.

Prime Minister Narendra Modi is hoping to win a third successive term, but opposition parties say Indians face the loss of many freedoms if he stays in power.

Which parties are standing against Narendra Modi's BJP?

Recent opinion polls suggest Mr Modi's Bharatiya Janata Party (BJP) and its allies will win the election for the Lok Sabha - the lower chamber of India's parliament - for a third time running.

The Lok Sabha chooses the prime minister, who in turns chooses government ministers.

In the 2019 election the BJP won 303 seats, and the coalition of parties it is in, the National Democratic Alliance, took 352 seats overall.

The main challenge in 2024 comes from a coalition of political parties headed by the Indian National Congress, the biggest opposition party.

More than two dozen parties have joined it to form the Indian National Developmental Inclusive Alliance ("India" for short).

Key politicians in this group include Congress president Mallikarjun Kharge, as well as siblings Rahul and Priyanka Gandhi, whose father was the former prime minister Rajiv Gandhi.

Their mother, Sonia Gandhi, is a powerful opposition leader but is not expected to campaign as hard as she did in 2019.

Delhi's governing Aam Aadmi Party (AAP) is part of the coalition, along with several important regional parties.

Three AAP leaders have been recently arrested, accused of corruption. The party accuses Mr Modi and the BJP of conducting a political vendetta against it, which the BJP denies.

What are the key issues and why does the India general election matter?

Mr Modi can claim India's global standing has risen thanks to its growing economy and closer relations with the US, which wants India to be its ally against China.

He has recently introduced generous welfare schemes, such as providing free grain to 800 million of India's poorest, and a monthly stipend of 1,250 rupees ($16; £12) to women from low-income families.

Rahul Gandhi is one of the leaders of the "India" coalition of parties challenging the BJP

In its manifesto Congress argues that unemployment remains high, especially for young people.

And it promises increased welfare payments for women, three million extra government jobs and more apprenticeships for college leavers.

It also promises that it will stop India's "slide into autocracy".

Minority groups say that they often face discrimination and attacks, and have been forced to live as "second-class" citizens under Mr Modi's rule - an allegation the BJP denies.

The campaign group for international civil liberties, Freedom House, says that journalists and others who question the BJP government have increasingly been harassed. It classifies India as only "partly free".

What are the dates of the polling days, and why does voting take so long?

Voting is taking place in different parts of India on seven polling days: 19 April, 26 April, 7 May, 13 May, 20 May, 25 May and 1 June.

The results will be announced on 4 June.

Voting is staggered to enable security staff to guard polling stations across the country.

Millions of electronic voting machines will be used, which let people choose between candidates or pick "none of the above".

Who can vote in elections for the Lok Sabha?

India is the world's most populous country, with 1.4 billion inhabitants, and 969 million of them can vote in this year's election - roughly one in eight of the global population.

Voters must be Indian citizens, 18 years of age or older and be on the electoral register. They also need valid voter ID cards.A simple guide to India's general election

969 million people are eligible to vote in India's 2024 general election

The 13.4 million Indian citizens who live abroad can also vote, but must register and return to India to do so.

There are 543 elected MPs in the Lok Sabha, and an individual party or coalition needs at least 272 seats to form a majority to govern.

Members of the Lok Sabha are elected for a five-year term to represent a single constituency, the winner being the candidate with the most votes.

There are 131 seats reserved for MPs from so-called "scheduled castes" and "scheduled tribes". These are groups officially recognised as disadvantaged, and make up about a quarter of India's population.

India has also passed a law to allocate a third of the seats to women, but this will not come into force for several years.

How are all the votes collected across India?

India is 1.3 million sq miles (3.3 million sq km) in area, and electoral rules say there must be a polling booth close to every human habitation.

The 2019 elections had a polling booth in a remote forest area of the Gir National Park in Gujarat for the one man living there.

In the 2024 elections, officials will trek 24 miles (39km) to a village in Arunachal Pradesh state in north-east India, to collect the vote of a single female voter.