1.What do i need to remember when pledging? And what are the drawbacks. I have read What is pledging and how does it work?
2.Who and why, is providing collateral aganst shares without interest (Since for gold loan, for pledging they take interest rate)
3.since i will be using collateral for intraday,what will happen if i book intraday loss and money gets deducted from collateral?
Hy @Prat10
you can check on this the link to for the details of haircut on the stocks you pledge.
I would not call it drawbacks but some important points:
You will not be able to use this margin to buy Options and only trade in MIS for EQ segment.
50% of the margin needs to compulsorily come in cash and the remaining 50% can be in terms of collateral margin. If you don’t have enough cash, your account will be in debit balance and there will be an interest charge also called delayed payment charges of 0.05% per day applicable on the debit amount. You can check on this link to know more about interest charges
Its a win win situation according to me as client would have another option to trade more and can gain more profit. For a broker he can earn some brokerage 
if you start running trading losses on F&O using collateral margin, and don’t provide the requisite marked to market (MTM) additional capital, your position would be to squared off your pledged holdings to make up for the losses.
This is only for FnO positions only,right ? What about intraday cash.
1.Lets say i have 10,000 in cash balance and got 40,000 in collateral after haircut…total 50,000
Will i be able to take 1.5lac worth of intraday equity trade with 5x margin ? (Similar to taking trade of 1.5lac with rs.50,000 and 0 collateral and 3x margin.)