Kolkata: Within a month of the Majerhat bridge collapse here in West Bengal, that claimed three lives, an under construction bridge in South 24 Parganas collapsed on Monday, police said. “Part of the under construction bridge over Kalnagini river in Kawkdeep area collapsed at around 10 a.m. No one has been injured in the incident,” a state police officer said. “The reason of the collapse is yet to be ascertained. Senior officials have reached the spot,” he added. A portion of the Majerhat bridge in south Kolkata collapsed on September 4, killing three and injuring at least 19 others. Another canal bridge collapsed in Darjeeling district’s Siliguri on September 7, injuring a truck driver.