Police said that the incident took place at around 9.According to the doctors of Safdarjang Hospital, Rekha had sustained 30 per cent burns, while Deepali received 40 per cent burns.It was the neighbour of the victims who had  called up the police station and also rescued the children from their home.Police investigation revealed that the four children were studying when there was load shedding in the area.According to the Delhi police, Lucky, asked one of his sisters to light a candle as they had to finish studies for a school test to be held the next day. His sister lit the candle and kept it on  the plastic cooler inside the room.The police, upon reaching the spot, immediately rushed the two sisters, who sustained grievous burns, to the hospital. While the father works as a driver, the mother works as a domestic help..The children continued with their studies without realising that the plastic cooler had allegedly caught fire and the fire was spreading rapidly.Presently both the sisters are undergoing treatment in the intensive care unit (ICU) of the hospital. The injured children have been  greenhouse netting  identified as Ashu, Lucky, Rakhi and Deepali.A police officer, who came to the spot, said that while the boys were discharged after first aid, while the condition of the girls was so bad that they had to be admitted to Safdarjung Hospital.Within no time, the fire engulfed the entire room. Crying to reach safety, the two of the boys managed to escape.But the two sisters, Rakhi and Deepali, sustained burn injuries in the incident and so did the younger brother.20 pm.New Delhi: Studying in candlelight had nearly cost the lives of four siblings, including two sisters on Monday night in Badarpur area.The police added at the time of incident their parents were not at home.