A passer-by informed the police control room and the woman was rushed in a PCR vehicle to the advanced trauma centre.
The accident took place around 2 pm when the two had stopped the two-wheeler near a traffic signal.
The crowd also pelted stones at two green DTC buses parked in the bus terminus.
Fifteen others were injured in the accident.
Two women, a 9-month old boy and two men died in the tragedy while many were injured.
Injured passengers said that the driver had been asked to take some rest after he was caught napping.
Driver had been handling a container with gasoline aboard the vehicle when bus caught fire.
Reports from Chamoli district said the injured are undergoing treatment at the District Hospital in Gopehswar.
Roadways bus carrying 52 passengers was going from Delhi to Guptkashi when the mishap occurred at Saknidhar.
The bus driver, identified as Kumar, has been arrested by the Indiranagar traffic police.
Seventeen persons were killed and twelve seriously injured when a bus fell 400 mts deep into a gorge near village Milla.
While most passengers suffered minor injuries, a few of them were referred to PGI and are said to be critical.
The 55-seat vehicle had 61 people on board when it overturned, and among the passengers, 12 were minors, police said.
Two buses collided at Partap Chowk flyover on Thursday injuring 12 passengers who were rushed to various city hospitals.
Police and rescue teams kicked off rescue operations and retrieved the dead and injured.