At least 134 people are killed and 170 rescued after a bridge collapsed in the western Indian state during Diwali celebrations.

Authorities in the western Indian state of Gujarat have arrested nine people in connection with the collapse of a suspension bridge, which killed at least 134 people.

Inspector General of Police Ashok Yadav said criminal investigations have been opened into people involved in the renovation and maintenance of the colonial-era bridge. He did not release the identities of the detainees.

Here are the main developments so far.

What happened?

The tourist attraction in the Morbi district of Gujarat is 1.25 metres (4 feet) wide and 233 metres (764 feet) long. It is known locally as the “Swinging Bridge” and was first opened in 1879 during British rule. It is located in Prime Minister Narendra Modi’s home state.

On Sunday evening, a crowd was sightseeing and taking pictures at the bridge. Some were holding its side cables when it crashed, plunging them about 10 metres (33 feet) into the Machhu River, videos from the scene showed.

Officials said at least 134 people died and 170 people were rescued, many of whom have been admitted to hospitals with injuries.

Sunday was the last day of the Hindu Diwali festival, and authorities estimated that about 500 people had gathered on the bridge to enjoy the festivities. Officials say the bridge had the capacity to hold 100 to 150 people at a time.

The bridge had been reopened on Wednesday after seven months of repairs by a private company.

What safety concerns have been raised?

Some people are questioning whether the company that carried out the renovation, the Gujarat-based electrical appliances and clock maker Oreva group, flouted safety rules.

Morbi’s municipality chief, Sandeepsinh Zala, said Oreva was under contract to maintain the bridge for 15 years. India’s NDTV news reported that the company had opened the bridge ahead of schedule.

“They did not give us any information that they were reopening the bridge,” Zala told Indian Express. “We have not issued any [safety] certificate to them.”

Indian Express also quoted an Oreva company official as saying: “While we are waiting for more information, prima facie, the bridge collapsed as too many people in the midsection of the bridge were trying to sway it from one way to the other.”

How has the government responded?

Modi, who is campaigning in the state for his Bhartiya Janta Party (BJP), is scheduled to visit Morbi on Tuesday. Modi was chief minister of Gujarat for 12 years, and elections in the state are likely to take place this year.

The BJP-run state government has formed a five-member team of police officials and bureaucrats to investigate the bridge collapse.

Haresh Jhala, a journalist based in Ahmedabad, Gujarat’s largest city, questioned why local authorities allowed the bridge to be reopened to the public.

“Four days have passed, and the local authorities were sleeping for so many days,” Jhala told Al Jazeera. “It seems the contractor was in a hurry to make money. … Whether the renovation was really completed or it was a trial, that is a matter of investigation.”

In a similar incident in 2011, 32 people were killed in Darjeeling in West Bengal when a crowded bridge collapsed. In the same state five years later, a flyover collapsed in West Bengal’s capital, Kolkata, killing 26 people.