Sept 10 (Reuters) - The Baltic Exchange's main sea freight index fell on Tuesday for a fourth straight session because of lower demand across vessel categories.
* The Baltic index, which tracks rates for ships ferrying dry bulk commodities, fell 29 points, or 1.2%, to 2,393 points.
* The capesize index dropped 50 points, or 1%, to 4,794 points.
* Average daily earnings for capesizes, which typically transport 170,000-180,000 tonne cargoes such as iron ore and coal, fell $457 to $35,664.
* The panamax index fell 30 points, or 1.4%, to 2,161 points.
* Average daily earnings for panamaxes, which usually carry coal or grain cargoes of about 60,000 tonnes to 70,000 tonnes, fell $241 to $17,315.
* The supramax index edged down 11 points to 1,319. (Reporting by Anjishnu Mondal in Bengaluru; Editing by Bernard Orr)