Kolkata, Aug 1 (IANS): The West Bengal government has sought help from scientists to crack down on the menace of rats boring deep holes at the base of a 380 metre-long key flyover in the eastern metropolis, an official said.

Built in 1963, the Dhakuria flyover in south Kolkata is one of the oldest concrete flyovers in the city and is a lifeline for commuters to and from Garia, Jadavpur and other areas in the south. It stands on inclining concrete walls filled with earth or sand.

"Rats are again boring holes. We have sought help from scientists. Nowadays the bridges are constructed on pillars but earlier they used to be on a support above soil," Firhad Hakim, Minister in Charge Municipal Affairs and Urban Development Department, Bengal, told reporters here.

In 2013, a portion of the bridge walkway collapsed prompting the state government to ask a central engineering consultancy company for a check-up of the structure.

Prior to the collapse, an investigation revealed rats had burrowed large holes underneath the structure that continues to function way past its retirement age.