Consolidated financial statements

First of all, AS 21 is applicable if and only if control i.e. relation of parent and subsidiary exists. You have mentioned that you need to consolidate because it is required by law of another country, in that case you should refer  law of that country only. Otherwise how will you meet the statutory requirements of that country.

There is no guidance at all in IGAAP.

But what will be the ideal method of removing the investments?...... if this is requested by the Management for analysis and not for any statutory compliance....

In that case to eliminate investments, you may opt the method given in AS 21.

Do give a note that although AS 21 not applicable in the current scenario but investments have been eliminated according to the principles of the same.