CHENNAI, SEPT 26: At least 11 passengers of an Indian Airlines flight on Chennai-Singapore sector were injured when the aircraft encountered heavy turbulence before making an emergency landing here this morning.The aircraft, with 187 passengers and 11 crew members onboard, returned to base here under `local emergency' conditions, after the turbulence led to a technical snag, IA and Airports Authority of India sources said. Of the 11 injured, nine had been hospitalised.Airport sources, however, said 37 passengers were injured but IA authorities maintained that only 11 were hurt.The flight encountered "heavy turbulence, bumps and jerks" 30 minutes after it took off from here, IA sources said.Capt Chandrasekhar, who commandeered the flight, immediately informed the Air Traffic Control at Chennai airport and was accorded permission to land.AAI airport director Sudhir Kumar said the flight made a "smooth landing" under "local emergency" conditions.He said an air hostess and a passenger who suffered minor injuries were treated as out patients.