A 70-year-old man was critically injured after falling 25 feet through a gap left by a missing slab on an overbridge footpath near Howrah Maidan on Wednesday evening but the government agencies have denied responsibility for the hole that is allegedly several months old.

Police and witnesses said the pedestrian, who was not identified till Wednesday night, did not see the 4ft x 3ft hole on the left side of the road approaching Chandmari bridge from Howrah Maidan and fell through it around 6.15pm.

Residents of the area said the bridge had been painted blue and white about a year ago but the missing concrete slab was not replaced.

The elderly man's fall was broken by cables hanging below the bridge. He was taken to Howrah District Hospital, where doctors said he had suffered head injuries and was unconscious and critical. The man, who has suffered several cuts and bruises, was kept on the floor of the surgical ward as no bed was available.

"We had informed the public works department about the missing slab but they said it was the responsibility of the Howrah Municipal Corporation," said Ahmed Tanvir Akhtar, a local resident. He alleged that when the civic authorities were alerted, they had said it was the responsibility of the railways.

Several thousand pedestrians daily use the footpath on the bridge that connects north and south Howrah.

The area was cordoned off by the police after the accident but another gap - large enough for a child to slip through - was left open on the same footpath a few metres ahead.

The wooden Chandmari bridge, built over the railway tracks, was turned into a concrete structure in 1933.

"We maintain the main structure of the bridge. The accident took place on the approach road, which is maintained by the state government agencies," said an official of Eastern Railway's Howrah division.

Officials of the PWD, which sources said is supposed to maintain the stretch, said they were not aware of the accident and did not know whose responsibility it was to repair the bridge.

"We don't maintain the bridge but tried to repair it a year and a half back after seeing its condition. But the RPF had prevented us from carrying out the repair. They had arrested six workers engaged by us," said Rathin Chakraborty, mayor of Howrah.