Singur: Six vehicles - a luxury bus, a car, a lorry, a Matador and an oil tanker - were involved in a series of collisions on National Highway-2 in Singur early on Friday that left at least six persons seriously injured.

The pile-up occurred on the busy Durgapur Expressway near Telipukur village in Singur around 7am, when the area was covered in a thick blanket of fog and visibility was poor, witnesses said.

Four of the injured, including the driver and conductor of the Matador, were admitted to Imambara Hospital in Chinsurah, Hooghly.

A Matador hit a sand-laden lorry from behind. The Matador, in turn, was hit by an oil tanker and swerved right under the impact before crashing into the lorry once again.

The Matador was carrying four vegetable vendors, on their way to the Howrah market with vegetables from Nalikul in Tarakeswar. The driver of the Matador, Samar Jana, and his helper Bablu Mondal had a close shave as the front portion of the vehicle was badly damaged. The windshield was shattered.

The passengers, however, jumped off the vehicle and escaped with minor injuries.

As the Matador slowed down under the impact of the collision, a gas tanker hit it from behind. The tanker was hit by a luxury bus coming from Bihar and headed for Calcutta and the bus by a car.

Police said all the vehicles were moving slowly, trying to negotiate their way through the dense fog, and so the impact was not too strong. "All the drivers had applied the brakes. We have sent the Matador and the bus for mechanical tests," a police officer said.

Police have started a probe into the accident.