A woman died and 19 others were injured after a Blueline bus caught fire in the Shahbad Dairy area of Outer Delhi on Friday.

The police said the incident was reported at 3.15 pm, when the bus, plying on the Old Delhi-Qutub Garh route, caught fire. “The injured include nine men, four women, and six children, among them a six-month-old infant. The woman who died has not been identified yet,” a senior police officer said.

The children have been identified as Gaurav, Gurmeet Singh, Hritik, Ajay, and Akash, the infant. The police said three fire tenders were sent to the spot and took about half-an-hour to douse the flames. The injured were sent to the Maharashi Valmiki, Bhim Rao Ambedkar and LN hospitals for treatment.

The police said that they are trying to find out the cause of the fire. Meanwhile, Kiran, a woman who was travelling in the bus, said a man who was carrying some combustible substance with him allegedly set himself on fire due to which the bus caught fire. “The man had a heated argument with the conductor after which he set himself on fire resulting in the incident,” she said.

Deepak, another passenger, said, “The rear of the bus caught fire first and everyone started running towards the front. Some got out through the doors while the rest broke windows in order to get out. I too had to break a window.”

“We are questioning the passengers as well as the driver and conductor and further investigations are on,” a senior police officer said. When contacted, Joint Commissioner of Police, Northern Range, Karnal Singh said, “Someone has given a statement that the fire occurred after a heated argument between two persons, one of whom was carrying a flammable substance. We are probing the matter from all angles; someone might have set himself on fire and a gas leak in the CNG bus lead to the fire.” Singh said a case under sections 336 and 304 A is being registered in connection with the matter against unknown persons.