NEW DELHI, Nov 18: At least 28 children died and 70 sustained injuries when an overcrowded bus carrying them to school plunged into Yamuna river after breaking through the iron railings on Wazirabad bridge this morning. The mishap, which has numbed the city, is the worst of its kind this year after the Uphaar cinema hall fire.The toll is likely to go up as many of the 120 children who packed the ill-fated bus that fell down about 25 feet below the bridge are still ``missing''. They do not figure either in the list of dead or survivors.The mishap occurred at around 7.30 a.m. when the bus (DL-1P-1644) coming from trans-Yamuna was proceeding for Shaheed Amir Chand Sarvodya Bal Vidyalya, Ludlow Castle no.2, at Rajpur Road. The bus, disclosed the eye-witnesses, swerved on its left when it drove over a patch of loose sand on the bridge. Within seconds the vehicle crossed over the footpath, crashed through the iron railings and fell down sideways into Yamuna.An eye-witness, Karnail Singh, claimed that the bus lost control after it tried to prevent head-on collision with another vehicle approaching from the opposite direction. ``I saw it turning suddenly, and then falling into the river,'' he recounted.According to unconfirmed reports, the driver - egged on by some children - was in a hurry to overtake a Blueline bus when the mishap occurred.In no time the bus submerged into the river, and along with it the cries of trapped children. But fortunately, help was at hand. A number of local fishermen who witnessed the mishap swam to the vehicles and pulled out a large number of children to safety.A full-fledged rescue operation was still on till late evening, with local fishermen, officials of police and fire departments and even naval divers pressed into service. Criss-crossing the dirty Yamuna waters on mechanised boats, as thousands of onlookers descended on and around the bridge, the divers were trying to pull out bodies that might still be stuck in the river-bed.The injured were rushed to Bara Hindu Rao hospital, where the condition of four of them is still critical. The bodies too were brought to the same hospital. According to the doctors, most of them died of asphyxia and were brought dead in the hospital.The fullest impact of the tragedy, however, was felt at Hindu Rao Hospital where the grieving families had gathered to collect the bodies of their children. Unconsolable, many of them were beating their chests, while some stood motionless in a corner, unable to come to grips with the tragedy. Their wails renting the air, many alleged that some children though still alive were callously dumped in the mortuary with the dead ones.But the doctors refuted the charge. ``most of the deaths,'' pointed out a doctor, `` were due to asphyxiation as water had entered the lungs. When there is lot of fluid, it tends to come out and you feel a person is actually breathing.''Kiran, mother of 11-year-old Krishan Kumar who died in the mishap was unconsolable. ``For the first time ever, he got the knot of his neck-tie right,'' she sobbed. ``I told him that he was looking good.He also took his lunch with him to school saying that he would eat it later. ''