A long section of an overpass under construction collapsed Thursday in a crowded Kolkata neighborhood and sent tons of concrete and steel slamming onto midday traffic, killing at least 21 people and leaving scores of others injured, police said. More people were feared trapped in the debris, and rescuers used saws, small cranes and their bare hands to search for survivors. Smashed yellow taxis, destroyed rickshaws and the bloody legs of trapped people jutted from the fallen girders and concrete. The overpass spanned nearly the width of the street and was designed to ease traffic through the densely crowded Bara Bazaar neighborhood. About 100 meters (300 feet) of the overpass fell, while other sections remained standing. It "came down with a huge crashing sound," said Yogesh Sharma, who was sitting at a roadside tea stand with friends. "I left my cup of tea and ran," said Sharma, a 23-year-old resident. "I was crying at the spot." At least 21 people were killed, a police official said on condition of anonymity because he was not authorized to speak to the media. More than 70 people were taken to two hospitals in Kolkata, the state capital, officials said. It was not immediately clear how many people were missing.