Traffic on the Vidyasagar Setu was hit on Thursday because a stretch of Kona Expressway, behind Nabanna, the state secretariat, was flooded after the afternoon showers.

Rows of cars, buses and goods vehicles slowed down on the bridge, which is in the midst of a major overhaul, as vehicles crawled trying to navigate the flooded pocket of Kona Expressway after crossing over the toll plaza on the bridge. Senior officers from Calcutta and Howrah police commissionerates intervened, trying to reduce the congestion that kept building, around 4.30pm.

With the rainwater continuing to collect, vehicles bound for Kona Expressway and the city slowed down, prompting officers overseeing traffic from Kolkata and Howrah police to send emergency alerts to PWD engineers and those overseeing the maintenance of roads in the Howrah Municipal Corporation.

“A stretch of Kona Expressway, after the toll plaza on the Howrah-bound lane, is low-lying and accumulation of water is almost inevitable. It’s like a cauldron in the middle with two sides of the expressway remaining slightly elevated,” said a senior PWD official.

Built to connect NH 117 to Vidyasagar Setu, Kona Expressway has remained a challenge for motorists because of a lack of a proper drainage system after a spell of heavy showers.

Last October, two underpasses of the expressway that were built a few months earlier, had remained flooded for several hours forcing vehicles to take an alternative route.

A pumping station, built to address the challenge of waterlogging could do little because the water that was pumped out found its way back to the expressway through the adjoining canals and high drains.

On Thursday, the accumulated water slowed down Howrah-bound vehicles on Vidyasagar Setu because of congestion on Kona Expressway, the police said.

“Movement of traffic on the Calcutta-bound flank also slowed down because of the diversion that has been put in place to facilitate the bridge’s repair work. One of the three lanes on the flank meant for Howrah-bound vehicles has been barricaded to allow Calcutta-bound vehicles to move. This has been done to allow engineers to work on repair cables of the bridge,” said a senior officer of Kolkata Police. “Heavy vehicles are allowed to move till 5pm before peak office hours set in. The presence of such heavy goods vehicles added to the congestion in the afternoon,” he said.

Besides Vidyasagar Setu, traffic towards Howrah Bridge, too, was hit during the day with water accumulating near the bridge’s approach on Strand Road, near North Port police station.

“Some of the manholes on the road were clogged with leaves accumulating around them in the aftermath of storms. This is not just about Strand Road but on several pockets on different roads across the city,” the police officer said.