If I buy an option contract using collateral margin, in which cases Kotak Securities can liquidate my collateral/position?

When you buy an Option contract using collateral margin, you can hold your position till expiry if you have sufficient trading margin in your account. However you need to add funds equal to the premium value within 5days of transaction date or your pledged shares will be liquidated on 6th day.
Trading Margin in your account can drop due following:

1. Due to increased haircuts on securities you have pledged (Example: Suppose you have pledged your Company A shares worth INR 1Lac. As per 15% haircut, you will get a margin of INR 85000. Using this margin, you buy a Nifty Option. If the haircut is increased to 20%, your margin benefit will be reduced to INR 80000. In case your option position requires a premium more than 80000, your collateral/position will be liquidated.)
2. If the value of the pledged securities has gone down. (Example: You hold Company A shares worth INR 1lac today and have got a margin of INR 85000 after 15% haircut. If your share value drops to INR 95000, your margin benefit will be reduced to INR 80750. In case your option position requires a premium more than 80750, your collateral/position will be liquidated.)
3. Option turns into ITM and delivery margin is charged in the last week of expiry (Applicable for Stock options only). Read here.
   Hence kindly make sure you have enough margins against your positions.