Navi Mumbai quarries are the biggest source of supply for crushed stones, sand and other construction materials. Pic for representational

With the closing of about 70 quarries in Navi Mumbai, the Brihanmumbai Municipal Corporation has fallen on rock-hard times. Road and other development works in the city have been hit as the civic body is running out of materials like stones and sand, after the Thane Collector shut down the quarries on March 30, following a lease expiry, lack of necessary environmental permissions and a pending case in the National Green Tribunal (NGT).