Holding the world's biggest democratic election is no mean feat, with 900 million Indians across the country eligible to vote between April 11 and May 19.

To iron out some of the hiccups of India's previous 16 national ballots — and increase public trust in the democratic process — the Election Commission has introduced a slew of new measures.

Take a look: Understanding 2014's Indian elections

Mug shots

With an estimated 300 million illiterate adults across India, photos of candidates will now feature alongside party symbols on electronic voting machines.

The devices have been dogged by claims they can be hacked, but will now print out a chit for each voter, who can confirm the details before dropping it in a sealed box inside the polling booth.

Random matching of the chits and numbers of votes on the machines should verify no tampering was done. Vehicles transporting the voting machines will also be fitted with GPS devices to monitor their movements.

Criminal candidates

In the outgoing parliament there were 186 lawmakers facing criminal charges or being investigated — some 112 of them involving serious cases such as murder or rape.

This time, candidates under a legal cloud have to issue three newspaper and TV advertisements detailing any charges they face in the constituency where they're standing.

The Association of Democratic Reforms (ADR) charity reported in 2014 that candidates facing criminal charges had a higher chance of winning elections compared to those without, either by intimidating voters or from buying influence.

Candidates have to declare income and tax returns for the past five years — the information is made public before the vote — as well as submit details any of assets and liabilities in their name abroad.

Citizen monitors

Webcams broadcasting live on the internet will monitor 5,000 polling stations and all counting halls, allowing voters to keep a close eye on proceedings in real time.

A smartphone app will allow citizens to record any polling misconduct or malpractice such as distributing liquor or drugs, a common method of vote buying.

The complainant, who can remain anonymous, can upload a photo or video to the app and officials are obliged to respond with action taken within 100 minutes.

A toll-free helpline number for voter information, feedback and complaints will also operate for the first time.

Apart from citizen monitors, some 3.7 million polling staff were involved in running the 2014 election.

Social media

India is Facebook's biggest market, with smartphone use exploding since the last election thanks to the world's cheapest data tariffs.

Candidates have to declare their social media accounts in legal filings when they apply to become an election candidate. This is aimed at monitoring and ending the misuse of social media during the polls, in a country where online misinformation is rife.

Facebook adverts

Social media advertisements will be scrutinised and vetted by the Election Commission.

Political advertising on social media will be considered a formal part of the campaign in the upcoming polls, unlike in 2014, and subject to rules and regulations.

Facebook India has said it will run “published by” or “paid for by” disclaimers on political advertising to increase transparency.

The new policy will also apply to Instagram, the photo app owned by United States tech giant.

Transgenders

Nearly 39,000 voters have registered as “third gender”, the first time they have been able to after a 2014 Supreme Court ruling that formally recognised transgender Indians.

There are around half a million transgender people in India, but previously they had to register as either a man or woman.

Women only

Female participation in Indian politics is low and just 59 lawmakers out of 543 in the outgoing lower house of parliament are women.

This year every constituency across the country is required to have at least one voting centre reserved for females, while the southern state of Karnataka has gone even further and will boast 600 women-only polling stations, including staff and security.