The police suspect poor visibility due to dense fog in the early hours could be the reason behind the accident.
The car, with nine people, was returning from a wedding in Cooch Behar when the truck, laden with stone chips, rammed into it, a police officer said.
Five died on the spot and four were rushed to North Bengal Medical College and Hospital with critical injuries. Among the dead are two children and three adults.
The four bodies have been sent for autopsy, he added.
Disclaimer: No Business Standard Journalist was involved in creation of this content