pbr Police and rescuers are continuing their search for survivors in the debris of a four-storey apartment building that collapsed in a congested neighborhood in New Delhi.br ppbr At least 61 people have been killed and another 83 others were injured as the 15-year-old building in the Lalita Park neighborhood collapsed into a mountain of concrete slabs, iron rods, bricks and mortar.br ppbr The building housed about 200 people - mostly migrant workers and their families - and about 30 people were believed still trapped under the rubble, according to officials.br ppbr Emergency efforts were hampered because fire engines had difficulty navigating the neighbourhood's narrow alleyways.br ppbr Local residents who were first to arrive at the accident site used bare hands to scoop away debris until they were joined by police and firefighters, who used gas cutters to cut through the iron rods.br ppbr Police brought in sniffer dogs to locate people trapped under the debris. Residents helped carry the injured to vehicles and to transport them to nearby hospitals, as hundreds of people crowded around or peered down from rooftops of nearby buildings.br ppbr Officials said it was not immediately possible to say what caused the accident but said there would be an inquiry.br ppbr Poor construction material and inadequate foundations often are blamed for building collapses in India. In New Delhi, where land is at a premium, unscrupulous builders often flout building laws, adding additional floors to existing structures.