Explain the controversial mode of acquisition - accession

The ontroversial mode of acquisition is accession. It involves the peaceful transfer of territory from one sovereign to another. The state which acquires territory in this way cannot gain more  rights  over  the  land  than  possessed by  its  predecessor. For  example,  at  the  time  of independence of Kashmir, Lord Mountbatten promised a sector of land to be given to Pakistan but still the problems pertain regarding it whether it belongs to India or Pakistan. Similarly, Hong Kong was given by China on lease to Britain and at the expiry of the said lease agreement, it reverted back to China. Similarly, in 1965 Pakistan gave Ladaaq under a treaty to China.