On New Year’s Eve of 2013, Shanghai authorities sent about 6,000 city police officers and requested help from military police to manage a 300,000-strong crowd that filled the city’s famed riverfront for the annual midnight light show. According to state media, police choked off access to an elevated viewing platform reachable through staircases and closed the nearest subway station to rein in the crowd.

But on Wednesday night, just as many revelers showed up to ring in 2015, and the venue was guarded by only 700 police officers with no traffic control, state media reported. People were free to walk up and down the staircases, and the closest subway station was left open.

The city had already canceled the light show on the Bund, as the riverfront area is known, and apparently downgraded police deployment and crowd control measures. When the authorities became alarmed by the huge crowd, they called in another 500 police officers — but it was too late.

Three dozen people ended up trampled or asphyxiated to death in a stampede at the bottom of a 17-step, 16-foot-wide concrete staircase, shocking a city proud of its professional urban management and a country eager to show off its most cosmopolitan city.

While investigations continue into the New Year’s Eve tragedy, eyewitness accounts and state media reports point to a sequence of miscalculations by city officials that helped create the out-of-control conditions leading to the stampede.

A woman offers prayers during a memorial ceremony on Saturday for people who were killed in a stampede during a New Year’s celebration on the Bund in Shanghai. (Aly Song/Reuters)

For three New Year’s Eves in a row, Shanghai hosted the spectacular midnight show on the Bund, but authorities canceled it last week because of worries about overcrowding and security threats. Instead, authorities opted for a smaller light show to be held at a nearby venue that required admission tickets.

Local media in Shanghai reported on the plans for the scaled-down light show several days before the event but did not give many details, according to the financial news magazine Caixin. The new venue also has a similar name to the Bund, which may have added to the confusion.

Authorities say investigations into the tragedy are ongoing, but patrol officers have confirmed that the city downgraded police deployment on the Bund on Wednesday night.

“Because there was no scheduled event, there was no traffic control,” patrol officer Wang Qiang told state media.

At around 11:20 p.m., as huge crowds gathered, authorities reminded them that the annual light show on the riverfront had been canceled. But 10 minutes later, surveillance video showed a massive jam of people on the steps at the end of a public square, leading to the best vantage point to view the Huangpu River and the skyscrapers across the water.

At around 11:35 p.m., people fell row by row on the steps under the crush of the crowd, survivors and eyewitnesses said.

“It was unstoppable. The force from above fell on us,” recalled Zhao Weiwei, a survivor whose girlfriend, Pan Haiqin, died in the stampede. “There might have been two to three security people. That was virtually none.”

— Associated Press