Indore: Two workers were killed after a portion of an under-construction tunnel on the Indore-Ichhapur highway near Simrol collapsed trapping them under the debris on Wednesday morning.DSP Umakant Choudhary said, "The incident took place around 4 am at the 4.1-kilometre-long tunnel being constructed on the Mhow-Sanawad section. A portion of the tunnel caved in, killing two workers."The construction work was underway by a Hyderabad-based company, he said. The deceased were identified as Vikas Rai, 29, from Jharkhand's Giridih district while the other was Lalji Kaul, 26, from Singrauli in MP. Kaul was critically injured and initially admitted to a hospital before being referred to MY Hospital, where he succumbed to his injuries.