A Nepal-bound bus rammed into a truck on the Agra-Lucknow Expressway in the midst of a dense fog cover over Unnao in Uttar Pradesh on Monday, leaving the driver and three Nepalese citizens dead, officials said.Six other passengers, four of them also from Nepal, got injured in the incident and have been hospitalised, they said.Additional Superintendent of Police Shashi Shekhar Singh said the bus carrying 60 passengers was going from Rajkot in Gujarat to Nepal.