Uttarkashi, July 16 -- A 21-year-old worker from Jharkhand died after being trapped under a collapsed section of concrete (shotcrete) lining inside the Silkyara Tunnel in Uttarakhand's Uttarkashi district, the District Emergency Operations Centre (DEOC) said on Thursday.

According to a preliminary report, the accident occurred at around 2:00 am when a portion of the tunnel's concrete lining collapsed nearly 900 metres from the Barkot side during ongoing work.

The worker was trapped under the debris and died in the incident, officials said.

The National Highways & Infrastructure Development Corporation Limited (NHIDCL) is conducting a detailed investigation into the incident and preparing a report.

According to the DEOC, the exact caus...