If my brother transfers money in my account, say 50 lakhs, will it be taxable in India?

No, if your brother transfers money to your bank account, it is not taxable in India. However, if the money is considered as income from any source, it may be taxable. For example, if the money is given to you as a gift, and the total amount of gifts received in a financial year is more than Rs. 50,000, it will be taxable as per the Income Tax Act. But, if the money is a loan, it is not taxable, but you have to ensure that you pay it back within the stipulated time. It is always advisable to consult a tax expert for any taxation related matters.