The United Kingdom observes British Summer Time from the last Sunday of March till October, when the clock is pushed forward to give residents an extra hour of daylight. This practice probably saved the life of Koushik Bhattacharya in Kolkata on Thursday.

Bhattacharya, who works as an associate position at British Telecom in Kolkata, usually leaves his home in Girish Park at noon. But because the UK had adopted BST from Sunday, he had to get to his office an hour earlier. It was only when get got to his office on Thursday that he learnt that a 100-metre section of the under-construction Vivekananda Road flyover on his street had collapsed, crushing scores underneath and damaging a section of his house.

“I rushed back from office to absolute pandemonium," Bhattacharya said. "I was almost in a daze – my only thought was to get back home and see if my family was alright. Thankfully, none of them were in that part of the house which was damaged. My father was having breakfast. All of a sudden, he saw the bridge moving towards him and rushed out of the room with my mother. Everyone is safe, maybe thanks to God.”

But the trail of destruction in front of his house left him horrified. “So many people were in this stretch when it collapsed," he said. "There were so many cars underneath, there were hawkers and beggars in front of the temple, and labourers working on top of the flyover. As they are removing the girders now, you can see chunks of flesh come out. It is the most horrifying thing I have ever witnessed.”

Difficulty in rescue work

On the ground on Thursday evening, rescue teams worked energetically, trying to cut through the mangled remains of the flyover. But other problems surfaced. Girish Park is a narrow, congested area in North Kolkata, an older section of the city. The road to the disaster site had not been shut. So gawkers milled around in their thousands, hoping to catch a glimpse of the tragedy.

“We are blocking the road [from the Metro station] but they still continue to troop in,” said a frustrated Rajiv Mondal from the West Bengal Police. “They come and take photos to put on Facebook and block the access points. Ambulances are taking more time to come in and because of this massive crowd, we have to be slow and careful. We obviously can’t afford to hit a pedestrian right now!”

As people continued to stream around, a few volunteers, brandishing lathis, attempted some sort of crowd control. But it had little effect. Onlookers pushed forward, desperate to get as close as possible to the site of rescue operations.

“How do we stop them?” said another police officer. “We do one lathi charge and they come streaming in from another alley. It is making it difficult for us to clear the area properly.”

Gruesome tales

The area's residents all had gruesome tales to recount. “I was in my father’s grocery store,” said Soumya Khan, a student who lives in the area. “Around 12.30 pm or so, we heard a loud sound and even felt vibrations. At first we thought it was an earthquake but then we heard a commotion – people shouting and saying ‘Bridge bhenge gache’ [The bridge has collapsed]. We rushed and saw that the entire stretch had become empty. People were rushing away from the area, scared that the entire bridge would collapse. I saw a woman, drenched in blood, stagger towards me.”

The section of the planned 2.2 km long flyover that collapsed was meant to connect North Kolkata to Howrah, running through some of the city’s most congested areas. But it had already undergone significant delays. Since 2009, construction has occured only in fits and bursts. A representative of IVCRL, the Hyderabad-based construction company that was contracted to build the flyover, claimed that the tragedy “it was an act of God”, but locals were not willing to buy that argument.

“From Wednesday night, they were casting cement on top of that fateful section,” said Aritra Seth who lives in the area and was among the first to rush there to help victims. “It was being done unevenly. One arm fell on Thursday and the other followed it, seconds later There were tram-lines running underneath, maybe the repeated vibrations of the trams underneath caused the flyover to collapse? Whatever be the case, this is Kolkata’s most horrific disaster.”

There were claims that the authorities had been late to start the rescue operations. “For the first one hour, it was only the locals trying to retrieve people with whatever makeshift tools they had at their disposal," Seth said. "The police arrived an hour later but even they did not have the tools to dig the people out. The first crane which arrived had to turn around and come back again. Precious time was wasted.”

Those pulled out were taken to the Medical College and Hospital in Chittaranjan Avenue. A junior doctor who was attending the Emergency ward on Thursday evening said, on condition of anonymity, “Most of the bodies received had severe lacerations. Almost all were dead on the spot. There were burn injuries as well on some of the bodies, possibly caused by diesel engines catching fire in the rubble down below.”

Work continued through Thursday night as rescue teams from the Army and the National Disaster Response Force tried to break through the remains of the bridge and retrieve as many injured as possible. The official toll is 21 but is likely to rise.