One person was killed and three others were injured on Saturday after a slab from an under-construction Metro Line 4 bridge collapsed onto vehicles in Mumbai’s Mulund area, officials said.

The incident occurred shortly after noon on LBS Road near the Johnson and Johnson factory. According to police and civic authorities, a slab of the parapet wall of a girder bridge fell onto a passing autorickshaw and a Skoda car.

Both vehicles were heavily damaged. Fire brigade officials identified the deceased as Ramdhan Yadav. The injured were named as Rajkumar Indrajeet Yadav (45), Mahendra Pratap Yadav (52) and Deepa Ruhiya (40).

Rajkumar is in critical condition and admitted to an ICU at a nearby hospital. Mahendra and Ruhiya are stable.

In a statement, the Mumbai Metropolitan Regional Development Authority said a portion of the parapet segment fell at 12:15pm near pier 196 of the metro line construction, close to Mulund Fire Station, onto a passing autorickshaw.

“The Metro project team is at the site and is working on relief operations and securing the site in close co-ordination with BMC and disaster management authorities,” the statement said, adding that an investigation is underway to ascertain the exact cause of the collapse.

Metro Line 4 is an under-construction corridor connecting Wadala in south-central Mumbai to Thane.

A substantial stretch of the line runs above the busy LBS Road, which links Ghatkopar, Vikhroli, Bhandup and Mulund, and carries heavy traffic through the eastern suburbs.

The collapse disrupted traffic for several hours as emergency teams cleared debris and secured the site.

Attacking the state government, Shiv Sena (UBT) leader Aaditya Thackeray said a wall had collapsed and the then newly inaugurated metro line 3 had got flooded amid heavy rains last year and asked if the BJP-led dispensation would blacklist the contractor (for today's incident).

"Not likely- may be it'll show a penalty of a few lakhs and let the contractor get more tenders," Thackeray said.

"If you notice, pillars are already painted- before the work was completed. This will cost the state some crores and then once work is finished, crores again to do them up," he said.

Even today, most infrastructure works have terrible barricading that either lead to traffic jams or vehicles falling into open pits, Thackeray alleged.

"Life has no value under the BJP regime. Falling pieces from metro lines, unsafe modes of transport, cars/ bikes falling into open pits with no help for hours. What a shame! Soon a day will come when countries will issue travel warnings for such things in our country too," the Woli MLA said.

Congress leader Varsha Gaikwad criticised the state government over the incident and questioned whether the lives of Mumbai residents had “become so cheap”.

In a post on X, she said authorities were more focused on publicity around infrastructure projects than ensuring public safety.

The Lok Sabha MP demanded accountability from authorities, raising concerns over alleged lapses in safety measures at the site, particularly given the heavy traffic movement in the area.

She also questioned whether quality and technical safety standards were being compromised in the push to complete metro works quickly, and said repeated announcements of inquiries after such incidents were not sufficient.

"While development is necessary, it should not come at the cost of citizens' lives," she said while calling for strict action against those responsible for the lapse.