A portion of the under-construction flyover from Byculla to Parel collapsed at Lalbaug on Tuesday evening, injuring three persons. Four vehicles were damaged.
About 5.45 pm, the driver of a crane on the flyover lost control and hit two pillars, causing a concrete beam to fall on to a taxi, a motorcycle and two cars waiting at a signal.
Amita Trehan, 48, was going to Ghatkopar from her Lower Parel office when the beam fell on to her car. "A part of the car has been smashed," she said.
Shaukat Shaikh, 29, owner of the damaged taxi, said he had bought it a week ago and paid his first instalment of Rs 10,000.
Biker Prakash Potdar, 31, said he slipped and suffered minor injuries on his shoulder. Two pedestrians were also hurt.
The Mumbai Metropolitan Region Development Authority (MMRDA), which is building the 2.4-km flyover, called the incident "minor." Dilip Kawat-khar, MMRDA spokesperson, said: "A part of the flyover fell while launching the girder. People suffered minor injuries."
The flyover, expected to be completed by December, will be longer than the JJ flyover.
Bhoiwada police said they would register a case of negligence against the contractor.