The incident occurred late last night but none of the around 30 passengers of the bus was injured, a senior police official at Lonavla police station said.
"The driver stopped the bus in the nick of the time after detecting smoke emanating from the vehicle and all the passengers got down before fire engulfed the bus," he said.
The official said vehicular traffic on the road was halted for 30 minutes and was resumed after firemen doused the fire.
Avani Jena, one of the passengers, who had boarded the bus from Vile-Parle in Mumbai, said as soon as the vehicle reached near Amrutanjan bridge, there was burning smell inside it and air conditioner too stopped working.
"The driver halted the bus, got down to see what had happened and immediately told us to get down. Without wasting time, all passengers alighted the vehicle," she told PTI.
According to police, the exact reason behind the fire will be ascertained after investigation by transport department officials.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)