''You tell me a bigger event?'' says Dr S. Y. Quraishi, who retired as India's chief election commissioner in 2012. ''We're talking about 814 million voters. That's more than the voters of all 50 countries of Europe put together.''

Christmas, Quraishi concedes, might be a bigger global event, but celebrations are individual, and not organised by a central authority.

''Even if not everyone votes, all 814 million voters who are registered have been physically reached by us, their forms taken, their pictures taken, their voter ID card given back to them, and then we have to provide the physical facility for all of them to go and vote. This is the biggest human event of the world. It's not just an election.''

Quraishi is twitching with excitement as he explains the details of a process remarkable not just for its size but its elegance.

Every vote - excluding those of Indian diplomats and defence personnel abroad - is cast on one of 1.9 million electronic voting machines distributed to 930,000 polling centres nationwide.

Double the size of an old portable typewriter, the EVMs display the candidates and their symbol.

''The machines are illiterate friendly. If the voter cannot read the name, he recognises the symbol, then presses the button next to the name. A light flashes, a beep sounds, and he exits the booth,'' explains Quraishi. ''We used to get so many informal ballots that sometimes they would outnumber the valid votes. Now, not one single invalid vote.''

Designed by a subsidiary of the Indian Defence Ministry for a trade union election in the 1980s, the poll was so successful the idea was presented to the election commission. After design input from another company, a special act of parliament was eventually passed and the EVMs replaced paper ballots in the general elections of 1998, saving 11,000 tonnes of paper.

The logistics involved in delivering the machines to polling stations in a country as topographically diverse as India are mind boggling, requiring planes, boats, trains, helicopters, elephants, camels, mules, and, when all else fails, foot. Physical obstacles include the Himalayas, deserts, malaria-infested jungles roamed by tigers, cobras, panthers, wild elephants, and, most deadly of all, armed Maoist guerillas in seven states who make a sport out of ambushing poll workers.

The first Muslim appointed to hold the title of chief election commissioner, Quraishi is the author of a book to be released next week titled an An Undocumented Wonder: The Great Indian Election.

''A lot of the wonder is about magnitude, but this election is about numbers big and small. Our smallest polling station has one registered voter. A temple priest who lives in a remote corner of Gujarat.''

Quraishi's favourite story of endurance and dedication to the task of giving every person the chance to vote comes from the last general elections in 2009. ''It was the last phase of voting, the last day, May 13, and on this day 100 million people were voting, but who were we most worried about? Just 37 people living in two villages in the Himalayas,'' he recalls.

Despite four attempts, bad weather prevented helicopters from landing the polling parties, so the only way in was by foot. Two separate parties of six were dispatched to the villages. For four days, the poll workers hiked through knee-deep snow to a height of 5000 metres, making it just in time to phone in the results when the national count began.

Which raises two questions most puzzling to the outsider - why are Indian elections conducted over such a long time - voting began on Monday and will progress through nine phases until May 12 - and how do you seamlessly count up to 800 million votes in a single day?

''We could organise the vote for one day, no problem,'' says Quraishi. ''The only problem is the security. We simply don't have enough armed paramilitary forces to protect 1 million polling stations at the same time.''

The reason there are nine phases in this election compared to five phases in 2009 is that more states have asked for special protection.

After each phase of voting is completed, the voting machines are transported to one of 4120 counting centres, where they are locked in a strong room and placed under armed guard until counting begins.

On the morning of May 16, poll workers at each counting centre across the country will start bringing the machines out of the vaults in groups of 15 at a time. Each machine will be unlocked, then verified by a returning officer and an independent observer.

The representatives of each candidate may also watch, but these days they are physically separated from the machine by steel mesh - ''to prevent the snatching and grabbing,'' says Quraishi.

As each machine is unlocked, it will print out an individual result. The result for each machine will then be simultaneously released to the media and transmitted to a national counting centre for the national tally.

''All the votes are counted by about 9pm, but we will know who will govern the country within a few hours, usually by around 2pm,'' says Quraishi.

Since India's first general election in 1952, voter turnout has averaged around 58 to 60 per cent but Quraishi predicts it may reach 70 per cent this year.