Inspect the hair closely. Blonde Indian hair always has a very few black hairs running through.
When Indian hair is dried with a blow dryer it becomes more "puffy" than Russian hair.
Bleach a thin strand of hair. The Russian hair will become lightest on the ends. Indian hair will become lightest at the roots.
At least 45% of all long Indian hair has split ends.
Dampen the hair, run fingers up the hair, then down. Unprocessed Russian hair will have a lot of friction when the fingers are run in an upward direction. Indian processed hair will have the same feel which ever way the fingers are run.
TEST FOR RUSSIAN HAIR vs. ASIAN HAIR
Asian hair is typically soaked in an acid solution to wear down the hair to appear thinner resembling Caucasian hair. This method is always hard on the hairs integrity and will only last a few days or weeks before it matts.
The same test of running damp fingers up and down the strands of hair to test for friction applies. The friction is minimal and feels very similar testing up and down the strands.
Under a microscope it becomes clear how much thicker each Asia hair is compared to Caucasian hair.
Caucasian hair and their cross-section under a videomicroscope
Asiatic hair and their cross-section under a videomicroscope