The speeding bus, carrying students of Kendriya Vidyalaya located in Karkadooma, turned turtle in Preet Vihar area of east Delhi at around 7 am.
A 50-year-old guardian of a student, identified as Sulaiman, was killed in the early morning accident, a senior police official said.
Out of the 24 injured students, 18 have been discharged after administering first-aid. Six children were admitted to three hospitals.
The driver of the bus fled the scene soon after the accident, the official said, adding that efforts were on to nab him.
Accidents, particularly bus accidents, are on a rise in the capital. On Sunday, a teenager and a 60-year-old woman were killed in accidents in the capital
At least six mishaps involving Blueline buses were reported so far in July. Blueline buses have been involved in around 60 fatal accidents so far in 2007.