Ketan Parekh is a person who was involved in the Indian stock market a long time ago. The stock market is a place where people buy and sell stocks, which are like tiny pieces of ownership in big companies.
Ketan Parekh was known for doing something called "stock manipulation", which means he would try to make the prices of certain stocks go up or down by buying or selling large amounts of those stocks. This is not allowed and is considered illegal because it can cause a lot of problems for other people who are investing their money in the stock market.
In the early 2000s, Ketan Parekh's activities were discovered by the authorities, and he was found guilty of violating the rules of the stock market. As a result, he was barred from participating in the stock market and was fined a lot of money.
Ketan Parekh's story is an example of why it's important to follow the rules and be honest when dealing with money in the stock market.