The accident took place when the Ahmedabad-bound bus was near Kuregaon village in Thane district’s Manor town, said Investigating Officer Sudhakar Yenare.
According to preliminary information, the accident occurred when the bus driver was attempting to overtake a Hazira-bound BPCL (Bharat Petroleum Corporation Limited) oil tanker and rammed into it, around 70 km north from Mumbai.
A speeding Verna vehicle behind the bus also lost control and hit the bus. Details of the car’s occupants and their fate was not immediately known.
Fire brigade officials and villagers doused the fire after the accident, which resulted in a massive traffic jam on the busy inter-state highway and other arterial roads.
The injured victims, two of whom are reported to be serious, were rushed to a hospital.
There were 21 passengers in the ill-fated bus, besides the driver and conductor. The condition of the remaining passengers and the bus driver and the conductor was not immediately known.
The bus, which left Pune for Ahmedabad around 6.30 in the evening, was completely burnt.
Senior district and police officials rushed to the site while officials from the Prasanna Purple Travels, the bus owners, were stranded in the traffic jam near Mumbai.
Police diverted traffic to the Wada-Bhiwandi Road and managed to resume limited traffic on the Mumbai-Ahmedabad Highway by 8 a.m.