It’s 3:13 a.m., and Radio Inspector Ashok Kumar turns around to look at his computer. His face stiffens. He zooms in on the screen and squints at an unauthorized SUV crossing a pontoon bridge.

Kumar and his team are in the Integrated Command and Control Center (ICCC) overlooking operations for this year’s Magh Mela, an annual Hindu pilgrimage and festival that draws millions of people in a single day. Each year, devotees from all across the country congregate at the spot where the Ganges, Yamuna, and mythical Saraswati rivers converge at Prayagraj, in the northern Indian state of Uttar Pradesh. There, devotees dip in the water, which they believe cleanses them of their sins.

It is here at the ICCC, a big white room with two rows of desks, that the police keep a vigil over the mela (the Hindi word for “fair”). At each terminal, policemen hunch over computer screens as they monitor feeds from around 700 closed-circuit TV cameras. A video wall dominates, with 55-inch screens arranged in a 10 by 2 matrix along the length of the room. Khaki jackets emblazoned with “Uttar Pradesh Police” hang on the backs of the chairs. Tapping their shoeless feet on the carpeted floor, the officers glance at each other regularly, followed by tentative nods implying that everything is fine.

The monitoring team is on high alert. Kumar and his team have been here since 8 p.m. last night, on a 12-hour shift, and the first bathing rituals began at 3 a.m. Today is February 9, and it is the full moon day of Maghi Purnima. Police are expecting a crowd of 7.5 million — down from a single-day peak of 11 million two weeks earlier. Millions of pilgrims will be leaving after today’s dip. Many are joined by their families, who have come to take them home.

Kumar’s job is to keep this massive crowd under control. Stampedes, terror attacks, and theft are on his mind. He places a call, and minutes after the SUV is vetted, a police officer appears on-screen to set up a barricade at the foot of the bridge.

Outside, as LED lights switch off, an easterly sunrise turns the sky several shades of crimson. On the water, the boats stand out in silhouette. The air contains a mix of piety and festivity.

The Magh Mela is a smaller version of the Kumbh Mela, the largest human gathering on earth. The Kumbh is held every six years, and the previous one was held in 2019. Over 49 days last year, more than 250 million people took a dip in the sangam, the point where the three rivers meet, with the biggest one-day crowd reaching 50 million. It was the second-largest gathering in history.

To prepare for the melas, tens of thousands of officials spend months setting up a massive temporary city on the banks of the Ganges. Viewed from above, it is a colorful patchwork divided by big and small bodies of water. Much of this — tents, floating bridges, and metal sheet roads — is built specifically for the festival. As the riverbed floods every year, the city lasts for only several months before the Ganges threatens to reclaim the land.

The physical structure of the mela changes each year, depending on the river. The groundwork usually starts in October, after monsoon season, when the Ganges retreats. Temporary roads are marked, and pontoon bridges are built to join land separated by water. Jetties are built on the banks; the roads are lined with metal sheets; pipelines and electricity cables are laid. Bathing stations are set up along a 3-mile floating jetty, with nets spread underneath to catch those who fall in.

This year, the Ganges’ water levels remained high later than usual. “We could reclaim land only by the end of November, but heavy rains kept hampering civil works until December,” says Rajneesh Mishra, a civil servant who oversees the mela. This year’s mela was spread over 270 hectares (667 acres), about 30% bigger than Monaco, and divided into six sectors for administrative purposes. Setting up the infrastructure was — and is — an immense logistical feat. The mela has 13 police stations, 40 police outposts, and five thermal power stations. There are five hospitals with operation theaters and 25 beds each, as well as labs, testing facilities, and on-site ambulances.

All of this requires a substantial budget. For this year’s mela, the state government budgeted $77 million. Last year, for the Kumbh, it spent $558 million.

All IT operations for the festival are run by the ICCC, which is based in a three-story concrete building that was inaugurated a little over a year ago by Prime Minister Narendra Modi. It’s one of the few permanent structures in the mela area, besides a temple and a 16th-century fort. The center itself is divided up between the monitoring room, which uses a video surveillance system to keep a bird’s-eye view on the mela; the wireless grid room, which liaises between monitors and the ground staff; the war room, where personnel from the fire, water, and police departments as well as the military are on hand at all hours to deal with emergencies; and, finally, a call center.

The key tool in the ICCC’s arsenal is the crowd management application (CMA) system, which keeps an eye on crowd density across all 700 camera feeds. The system is taught how much ground area each CCTV camera covers, which then allows it to estimate, with 85% accuracy, the number of people in a space at any given time. If there are more than three people per square meter, the system issues a warning, and the ground police team is notified and instructed to stop, hold, or divert the crowd.

The Prayagraj Smart City Mission team, which oversees the ICCC, considered various methods for crowd management before settling on the CMA. One option was to estimate crowd size by measuring an area’s smartphone density. But this idea was quickly scrapped. Most devotees at Magh Mela are not smartphone users, says assistant manager Vipin Singh. Only 500 million people in India — roughly one-third of the population — own smartphones. Additionally, many families share one phone, and rural residents (who form as much as 95% of mela attendees, according to police estimates) often don’t use them at all. “If the system shows three people,” says Singh, “there might actually be 100, where 97 are carrying basic mobile phones or no phones at all.”

Last year, officials also experimented with a facial recognition system. The idea was that the technology would provide accurate headcounts, track patterns of movement, and measure time spent between distinct points. But that didn’t work either, as people often carry big bags on their heads as they navigate mela crowds. That meant that, for every face the system could see, a piece of luggage might conceal several more.

Cars have proven easier to track. The automated number plate recognition (ANPR) system records the license number of every vehicle entering or exiting the city, checking it against a database containing the license numbers of stolen vehicles and ones involved in crimes. If a match is found, an alert goes off. For this Magh Mela, says Singh, the administration installed ANPR-aided cameras at eight locations on the city’s periphery. But there are plans to ramp up. “For the next mela,” he says, “we’re looking to increase this to 28 locations.”

It’s 7:17 a.m. Mamta Sharma stands knee-deep in the river.

Facing east toward the Ganges, she presses her hands in a namaste. She bows her head several times and chants a prayer under her breath. And then she takes a dip in the river, repeating it four times.

Seagulls glide over the heads of bowing devotees, but neither seem to mind the other. When pilgrims toss bits of fruit into the river, the seagulls scoop them up before they land in the water.

Some devotees hire boats to get to the point believed to be the exact location where the three rivers meet. There, people offer their respects to the river, take dips, and fill plastic cans with sacred water. At the sangam, you can see colors mixing, says boatman Ajay Nishad. “The whitish water is that of the Ganges, and the black that of the Yamuna,” he says. Stare long enough and one might think that he is right.

People who can’t afford to hire a boat, which is most pilgrims, instead bathe close to the bank. The mela administration encourages this to avoid overcrowding.

Sharma comes out of the river. Still dripping, she makes a video call to her mother, who could not come with her. She pans her phone to show the sangam to her mother, who offers namaste multiple times, her eyes welling up.

While she dries off, Sharma keeps looking up expectantly. On some auspicious days, the mela administration showers flowers on bathing devotees from a helicopter. She has seen videos of it on social media. “We were all excited about it, but it hasn’t happened today,” she says.

“Still, the holy dip is quite an experience.”

Sharma, who lives in Kolkata in eastern India, has come to the Magh Mela with a group of 12. They live in different cities but come from the same family in Jaunpur, over 100 kilometers from here. Most are elderly. At 31, Sharma is the youngest.

Nishad, the boatman, has been ferrying visitors to the sangam for three years, and he says the melas are always very well organized. Police designate holding areas to keep people safe when crowds swell and are good at managing foot traffic to prevent bottlenecks. While it can take several hours to find missing people — pilgrims getting separated is a common problem at melas — he says the administration always tracks them down.

But, lately, he has noticed something new. Officials have started using a lot of cameras, he says.

“Just look up,” he says, pointing to a drone hovering over the river. “It’s watching everything.”

It was at last year’s Kumbh Mela that the ICCC proved its worth. On Mauni Amavasya, the day when the mela drew a crowd of 50 million people, officials defused a situation that could have easily turned dangerous. Around 5 p.m., after the auspicious hour for the holy bath ended, millions of people left the mela and rushed toward the Allahabad railway station. Within minutes, it was overflowing.

Singh, the Prayagraj Smart City administrator, recounts that people weren’t able to move an inch. “It was a very tense situation,” he says.

Hanging over that moment was the memory of the 2013 Kumbh, when a stampede led to the death of 38 people at Allahabad railway station. The exact sequence of events remains contentious, but an inquiry found that North Central Railways authorities had underestimated the crowd size and hadn’t arranged enough trains, while the state government failed to deploy nearly 6,000 buses to relieve pressure. Police also bungled crowd management. This wasn’t the first time that such a tragedy had occurred: since 1820, there have been more than half a dozen stampedes at Kumbh Mela celebrations. In 1954, at the first Kumbh in independent India, up to 500 people died and more than 2,000 were injured when panic broke out.

This time, however, cameras equipped with artificial intelligence (AI) had already flagged areas where human density had reached unsafe levels and alerted officials about an impending stampede. It was the first time that an AI-based crowd management application had ever been used in India. Additionally, in advance of this year’s mela, railway authorities had collaborated with the Motilal Nehru National Institute of Technology to develop a crowd-simulation tool that could calculate the amount of time a person takes between entering the station and boarding a train. Extrapolating from that, they estimated that the Allahabad station could handle 10,000 mela passengers in an hour and took measures to keep people safe.

At the ICCC headquarters, authorities issued instructions to cordon off the Johnstongunj junction on the way to the train station and told police on the ground to form a human chain around a 15,000-person crowd. An additional 30,000 people were diverted to a 16-hectare (40-acre) garden to keep them away from the roads. To clear out the train station, the ICCC used camera feeds to estimate the number of additional trains the railways needed to run. By the end of the day, 75 trains had been added, and 300 passenger trains already scheduled to pass through the station were each set to accept between 500 and 1,000 departing pilgrims.

It took officials several hours to calm the situation, but by the end of the day, the roads and the railway station were cleared. A dozen devotees were injured when a small stampede broke out in another part of the mela, but no casualties were reported.

A major disaster had been averted.

Around 9 p.m. on February 4, a police constable in the monitoring room was watching the video feeds from the tent city. It had been largely an uneventful day until then.

With his eyes on the screen, the constable was chatting with his colleagues about the remaining two big bathing events. He was lamenting how many days were left for the mela and how many 12-hour shifts he still had to pull.

“What is it?” he said, to nobody in particular. He was already zooming in on a screen. Images of rising smoke came up.

“It’s a fire,” he shouted.

Immediately, he picked up the phone and called the wireless grid.

“A fire in a tent! It has just started.”

The smoke rose from a camp where thousands of devotees had pitched their tents next to each other.

Once the wireless grid was informed, they alerted the ground response team. Moments later, firefighters reached the spot and put out the fire. All of this took less than a minute, without pilgrims even noticing what was going on. “People in the tents were surprised to see them,” says SS Dubey, a fireman working in the war room.

Because so many people pitch tents at melas and cook their own meals, gas fires are fairly common. At least four have broken out this mela, says Ashutosh Mishra, Additional Superintendent of Police (ADSP), Magh Mela. In all of them, he added, “Our response time has been less than two minutes.” Before the ICCC, chimed in his colleague, Radio Sub-Inspector Sanjay Kumar, officials had to rely on tips from the public to learn about fires.

“By then,” he says, “half the mela could have burnt down.”

In addition to fires, police on the ground deal mostly with stopping petty crimes and preventing stampedes. Teams of police can be seen every 20 to 50 meters, says Mishra, and they are always in contact with the control room. This comes in handy if misinformation spreads, as officers can verify facts in real time and calm people down. “They can tell people, ‘We have asked the control room. Nothing has happened.’” It also allows them to more effectively address smaller problems, such as lost pilgrims or fake priests. With so much going on, Sub-Inspector Jitendra Kumar Gautam relies on the ICCC to be his eyes in the sky. “I’m covering a 1.5 kilometer area,” he says. “I try to be as vigilant as possible. But [without them,] how would I know where I’m needed the most?”

Throughout the day, a PA system close to the police watchtower, the tallest structure in the mela, continuously announces the names and descriptions of people who have been separated from their families. Once in a while, the microphone will be handed over to somebody looking for their loved one. “Aye Rahul ke papa! Hum Rahul ki mummy. Sun rahe hain; jaldi aaiye yehan.” (“Hey, Rahul’s dad, this is Rahul’s mum calling for you. Rush here quickly if you can hear me.”) In small-town India, it’s common for people to refer to themselves in terms of their offspring. It’s usually the oldest child who gets the honor of being mentioned.

This year, the police introduced a computerized missing-people center that uses a central server to match individuals with descriptions of lost people. The center, however, still had a few kinks to work out. That evening, the constable behind the desk was struggling to connect to the server. “This happens every day,” she says. Many of the police running the system weren’t well versed with IT or networking technologies and hadn’t received proper training. So the constable came up with another solution: she was passing information to the people running the PA system.

While the mela is equipped with all kinds of sophisticated technologies, certain time-tested “low-tech” solutions like the PA system still get the job done. Ultimately, the most important factor in the smooth operation of the mela is the institutional knowledge that has been gathered over decades, such as knowing where exactly to deploy security personnel and how to manage foot traffic. There’s perhaps an irony in the fact that a multi-million-dollar tech apparatus governs the experience of millions of devotees whose relationship with technology is peripheral at best. Yet as they attempt to release themselves from the cycle of rebirths and attain salvation, this is likely not top of mind.

Back at the Prayagraj City ICCC, assistant manager Singh walks around checking video feeds from mela exits and the railway station. He seems pleased with how crowd management has gone. While last year’s Kumbh Mela was instructive for his team, the much smaller Magh Mela has allowed them to experiment with and refine their tech.

“We’re using this mela to gather more data for deep learning,” he says.

As an example, he offers the problem of waste removal. To keep the mela clean, AI-enabled cameras have been set up and trained to recognize when a trash can is full. Additionally, the can uses an RFID tagging system to send a signal to a nearby garbage truck. Singh’s team is also developing a system that will automatically photograph anybody who litters. “We are internally using this to find out where littering happens so that we can clear it. Right now, we’re not looking to identify the persons responsible for it,” he clarifies.

The systems in place at the Magh Mela are just further examples of the growing role of surveillance tech in India. In a landmark 2017 ruling on Aadhaar (the national biometric identity card program), the country’s Supreme Court declared individual privacy to be a fundamental right. This, however, has not stopped the Modi government from expanding the use of surveillance, particularly facial recognition technologies, in daily life. In December 2019, police used the software to track people at a rally in New Delhi, and that same month, the federal government introduced the Personal Data Protection bill to empower them to collect anonymized personal data from companies.

Facial recognition systems are already in place at the Bangalore and Hyderabad international airports, and the Modi government is currently looking into implementing the world’s largest facial recognition system. In recent months, police have been using AI-based cameras and facial recognition technologies to enforce Covid-19 lockdowns in Pune and Hyderabad. N.S. Nappinai, a lawyer who specializes in cyber law at India’s Supreme Court, says that there are no specific laws or regulations currently governing the technology, and legal precedents have yet to be established. Nappinai warns Magh Mela attendees that “a substantial portion of personal data is being collected, retained, and used through facial recognition technology, not just during the mela but after too.”

Many pilgrims, however, are not aware of these controversies. And mela authorities routinely brush aside questions about data collection and privacy, redirecting conversation back toward security.

“We’re going to implement all our learnings to perfect tech solutions. The next Magh Mela will see an even better implementation of technology,” says Singh.

The day has wound down, and Mamta Sharma is pleased with her experience.

“Nowhere in the mela were we pushed around or rushed,” she says. “It is crowded, but we can keep walking. I was scared for the old people with me. But everything was just fine.”

“I don’t know how they organized the mela, but they did it very well.”

The mela will last for another 12 days or so, with another big gathering at the end. But devotees who came in just for the day are leaving. Pilgrims are vacating their camps; tents are being stripped of sarees and bedsheets; women are tying their belongings into neat little bundles, and men are loading them on vehicles. Some are rushing to fill the last can with holy water.

On the banks of the river, women squat as they offer evening prayers to the river. A bunch of young girls light earthen lamps and place them in the water. A couple married the previous night are still in wedding attire. They bow to the sangam for blessings. Around them, young boatmen are posing for pictures. One climbs on his dinghy and stretches his arms out like a Bollywood film star. An old man, clad in saffron, picks up a crutch from his scooter and stands to offer respect to the river. Before him, the golden waters of the sangam blend into the gray mist. The sun has set over the mela.