Altis is 1800cc and comes with optional equipment as standard which is unavaibale in GLi such as leather seats, sunroof, optitron, alloy rims etc.
GLi is 1300cc fully loaded but does not have any of the above mentioned features of the Altis. Altis also comes in non-sunroof package and you can also buy the Altis with automatic transmission. GLi only comes with manual.
Altis has airbags whereas GLi has none. However, both GLi and Altis are equipped with ABS with EBD.