A Malaysian Airlines plane with 158 passengers and crew on board had to land under emergency conditions at the IGI airport in Delhi today after one of its engines developed a technical problem.Airport sources said that the airline's Delhi-Kuala Lumpur flight MH 173 took off from IGI airport at 13.08 hours. After an hour of flying, the pilot noticed some technical problem and decided to return.He asked for emergency landing and the Boeing 737-800 aircraft landed safely at 15.02 hours.