SHEIKHUPURA, Aug 26: Four labourers drowned in QB link canal near Meeranpur here on Saturday. Reports said eight labourers were going by a tractor-trolley laden with wheat bags. Near Meeranpur the vehicle overturned on bank of the canal after crossing a broken small bridge. As a result of which, Salamat, Karamat, Abid and Asif fell into the canal and drowned. Their bodies could not be recovered. Warburton police are investigating.