There have been a few suggestions by the Indonesian officials on this - can you elaborate on which corporations exactly? I'm not saying that you're wrong, but I've not been able to find direct information on "non-Indonesian corporations" who engage in illegal burning, so if you have sources, that would be great.

It's a blame game.

Can anyone deny that the source of the fire originates from Sumatra Indonesia? Is Indonesia a sovereign nation or not?

If Indonesia says that it is not responsible for the fires because they are started by non-Indonesian corporations operating on Indonesian soil, then either you are very naive or Singapore would be fully justified in mobilizing its armed forces to deal with the situation.