The minimum quorum requirement to transact business in the Rajya Sabha (Council of States) is:

Under Article 100(3) of the Constitution of India, the quorum to constitute a meeting of either House of Parliament is one-tenth ($\frac{1}{10}$) of the total number of members of the House. For the Rajya Sabha (maximum strength of $250$), the required quorum is:
$$\frac{1}{10}\times 250=25\text{members}$$