Four persons of a family were suffocated to death late on Diwali night, when the fire from the lamps lit in their house in Kasumpti spread and burnt the plastic ware, releasing poisonous gases.The deceased have been identified as Naresh Kanwar (42), his wife Sunita (38), Akanksha (11) and Aniket (5). The neighbors spotted the fire early and informed the Fire Brigade, which reached the spot with 15 minutes. The victims were rushed to hospital, but were declared dead.Doctors said the family died by inhaling poisonous gases, released by the burning of plastic. Since there was no ventilation in the bedroom, the gases killed them fast. The incident occurred at about midnight. The family hailed from Jammu and run a small shop in Kasumpti.Some stock of the plasticware brought for selling during the festive season was stocked in their house. It caught fire from the lamps lit at the place of worship in one corner of the room, said the police. Senior officers of the district administration visited the spot in Govind Lodge today morning.The deceased were cremated by their family members in Shimla today evening. Meanwhile, three persons were badly injured when an HRTC bus went off-road near Vikas Nagar. The injured were admitted to IGMC Hospital. They have been identified as Rakesh, Parminder and Girish.Fortunately, the number of burn injuries caused by fire crackers was low this Diwali. Only about a dozen cases of burns were reported. Doctors said that luckily, there there only one or two eye injuries caused by the bursting of a cracker. These were minor, and the patients were discharged after first aid.Firemen were on high alert through the Diwali night, since the town has many old wooden buildings.