Two days after a chunk of the Majerhat bridge, a key connector between south and southwestern Kolkata, collapsed, killing three persons and leaving more than 20 injured, the West Bengal government made a startling revelation. After a meeting with officials of different Departments, Chief Minister Mamata Banerjee said 20 bridges in the city and its suburbs had outlived their life span.What is the problem?While the government did not name all the bridges that are operational and carrying traffic well beyond their expiry date, it specified three bridges at Sealdah, Ultandanga and Santragachi. These are three of the busiest flyovers and railway overbridges that carry thousands of vehicles and commuters every day. For the city, which is still grappling with three bridge collapses since 2013, crumbling infrastructure is a cause for concern.Why are bridges falling?One of the key problems, cited by the government, is that being a riverine State, it has hundreds of bridges, and many were built years ago, including some dating back to colonial times. For instance, the iconic Howrah Bridge, which was opened to the public in 1943, faced a peculiar problem earlier in the decade when its pillars started corroding because of spitting by thousands of gutkha-chewing commuters. The steel structure was made stronger by fibre-casing by the Kolkata Port Trust.The State government claims that documents relating to many bridges built before independence and during the previous governments are not available, and therefore the agency that is responsible for their maintenance cannot be located. The case filed by the Kolkata police in the Majerhat bridge collapse under several Sections of the IPC, including 304 (culpable homicide not amounting to murder), is against “unknown persons.” However, documents in the public domain suggest that the tenders for repairing the bridge were brought out by the Public Works Department earlier this year, but renovation was never taken up. Moreover, a fresh coat of blue and white (favourite colours of the government that adorn all public offices and infrastructure) paint on these crumbling structures, where vegetation, including trees are found to be growing, indicates that adequate measures for ensuring the safety of these structures have not been taken.Who is responsible?A close look at the urban infrastructure in Kolkata reveals that due to lack of road space, along with surburban and metro railway projects criss-crossing the city, many flyovers, railway overbridges and elevated corridors have been built. There are multiple agencies managing these structures: the Public Works Department, the Kolkata Metro Development Authority (KMDA), the Irrigation Department, the Kolkata Port Trust and the Railways. This often means that no one party can be held accountable for the sorry state of affairs. Another hurdle to repairs is that people have taken shelter under these structures and refuse to move.What is the government doing?The State government has set up bridge inspection and monitoring committees under the PWD, the Irrigation Department and the KMDA. These committees will be engaged in the safety audit of the bridges. The State government has also banned the plying of heavy vehicles and 20-wheeler trucks on bridges and flyovers of the city. The government has urged the Joka-BBD Bag metro project, being carried out in the vicinity of the Majerhat bridge, to suspend work till the inquiry committee, headed by the Chief Secretary, completes its investigation.What lies in store?Since the Majerhat bridge on Diamond Harbour Road connected Behala and the adjoining suburban areas to the city, the accident has resulted in traffic bottlenecks. The Transport Department has started bus services, but with the festival season approaching, the traffic police and the government will have to take more measures to ensure full connectivity to the southwestern suburbs.