Decoding "Doctrine of Necessary Accommodation" in a Sec 13(2) Scenario

Yaar, I've been struggling with this concept in our Judicial Services prep. Textbooks just say it's about accommodating state subjects, but woh kya bol rahe hain? Can someone explain with a real-life example? Suppose there's a state implementing a law to reserve 50% of seats in a professional course for locals. Can the central government ask the state to accommodate all-India quota aspirants, under the name of national interest? How far does this 'accommodation' go? I've seen it like this - if Centre wants, state has to adjust, but how much? Give me a practical example to help me understand this better, please!