KhasMahal Land as collateral security

I have applied for education loan to the SBI Bank and the loan amount exceeds 7.5lakhs and so they are demanding a collateral security. I have got a KhasMahal Land on my father's name but they refused to take that as a collateral stating that KhasMahal Land cannot be used as collateral security. Is this actually true? Also, my brother got the education loan on the same land papers as collateral security in 2019. Is some new rules introduced after 2019 where they stopped taking KhasMahal Land as collateral security. Please help!