Four workers were injured in Jammu and Kashmir on Friday when a portion of a tunnel under construction crumbled, police said. The workers were taken out of the rubble at Chenani, about 90 km from here, and taken to a hospital in Udhampur. The tunnel is part of a four-lane road widening project of the Jammu-Srinagar highway. The reason for the collapse was not known. (Inputs from PTI) The 12-km-long Chenani-Nashri tunnel is being constructed by a foreign company on J-K highway and over 40 per cent of the tunnelling work has been completed.