"It is suspected that a yellow powder-like substance was thrown at them from a train passing in the Up direction. This caused irritation as well as other symptoms of uneasiness leading to their falling off the train," railway authorities said in a late night statement.
The victims were travelling on Dadar-Thane local and the incident took place at about 7:55 pm.
The injured have been admitted to Bhabha Hospital and Sion Hospital. One of the injured persons died in the hospital, the release said.