14 years ago there were just 18 index based products in India. Today there are over 200. In the past year and a half the total corpus in index funds has doubled from 3 trillion rupees to 6.25 trillion rupees. That means these indices wield a lot of power as well. You can't do much about it unless you ban index funds or break up the concentration of power among a few select index makers. But that's not really a plausible solution so the only way out is to regulate them.