A 21-year-old labourer from West Bengal died while cleaning a manhole behind the market committee office here on Tuesday night, allegedly due to negligence.The worker, identified as Jahidul Shamim, was lowered into a nearly 10-foot-deep manhole around 9 pm, but he failed to come out.After nearly 16 hours of efforts, his body was retrieved around 1 pm on Wednesday.Fellow labourers alleged he had been sent alone into the manhole by a supervisor and a junior engineer despite the work not being assigned to them.The administration has constituted a four-member committee to investigate the incident.