At least 50,000 WhatsApp groups were created in a bid to reach three crore smartphones in Bengal.

The BJP gave a big fight in West Bengal winning 18 of the 42 Lok Sabha seats, bringing down the Trinamool Congress's tally from 34 to 22. The vote share of the BJP in the state stood at close to 40 per cent, an increase from 17 per cent in 2014. Keeping in line with the party's "Look East" policy, 40 per cent of Prime Minister Narendra Modi's campaigning was held in Bengal. BJP president Amit Shah also frequented his visits to the state.

The catalyst driving the PM-Amit Shah campaigning was the carefully coordinated effort by its social media team in the state.

Tucked away in a corner of North Kolkata is a three-bedroom flat that is the nerve centre of the social media cell of the BJP.

The election war room that began operations in 2018 comprised 10,000 people, who worked round-the-clock over the last eight months. Their primary target - to score at least 23 seats in Bengal.

Ujjwal Pareekh, a professional with a tech firm handling the account of a London-based Formula 1 team, leads the BJP war room. He is the convener of the BJP's IT cell in Bengal and takes orders from Amit Malviya, BJP's in-charge of national information and technology cell, and passes it down to his team.

Mr Pareekh said it wasn't easy to run the social media campaign in the state where the Trinamool Congress sent out notices to every dissenter. "We were constantly under threat. If any of our IT cell workers posted anything on Facebook, the very next moment they would get a call from the cyber cell. So what we did was, we carried most of our campaign through WhatsApp."

At least 50,000 WhatsApp groups were created in a bid to reach three crore smartphones in Bengal. Share-Chat was also used to send out messages in Bengali.

The official Twitter handle had two crore impressions in the last 60 days, Mr Pareekh said.

"There was a trickledown effect. Amit Malviya ji guided me; I did the same to the 42 people in-change at the Lok Sabha level. They in turn trained 294 people in the assembly level. There on, we had mandals, and finally the sakti kendras - a set-up to strengthen booth-level preparations. There are close to 13,000 sakti kendras, of which at least 10,000 of them had an IT team".

Along with their help in campaigning, the WhatsApp army ensured Mamata Banerjee's anger at people chanting "Jai Shri Ram" or memes of her comments went viral, he said.

"I have conducted over 80 workshops in the last 16 months across West Bengal to list out the dos and don'ts. Clear instructions were given that they were not supposed to spread information that was not genuine. All we needed to do was expose the failures of the Mamata Banerjee government, and put forward the PM Modi sarkar's agenda to the people," Mr Pareekh added.

While NDTV got a sneak peek into all that went into "2019 mein half" campaign, the 39-year-old IT cell head says the target for the team is now "2021 mein saaf", or halved in 2019 and wiped out in 2021. "For that, plans are already in place. We have reached around 45,000 booths with our messages in 2019. Come 2021, we want to dominate the conversation in all of 77,000 booths in Bengal," Mr Pareekh said.