As per reports, the incident took place late Wednesday when the chartered bus, carrying around 20 migrant labourers from different districts of West Bengal and Jharkhand, was heading to Lucknow.
Additionally, two persons were injured and were rushed to the Raiganj Medical College and Hospital.
Police said the migrant workers returned to their homes during the lockdown. They were now going back to their workplaces after getting both doses of the vaccination.
The bus was heading towards Lucknow, via Purnia and Patna in Bihar when the accident occurred.