Well, the current govt introduced black box, unlimited size, electoral bonds.
So pretty much anyone can spend billions to buy a bond, and then have it anonymously sent to their party of choice.
The party which has been spending the past several years building a rock solid link to corporate India is the BJP.
They're earnings the last year was greater than the other top 3 parties combined, if not top 4. Think it was nearly 400% growth.
For Chidambaram and his ilk, it seems his greatest fault was not thinking big enough.
I do agree that they are no saints. Its just the scale at which the BJP functions is so many step function increments higher, that its laughable to compare the two.