Describe the bases on which John Marshall, Director General Archaeological survey of India in 1924 announced the discovery of a new civilisation in the Indus valley to the world.

Explanation

(i) John Marshall, the then Director General of Archaeological survey of India did a lot of work in this area.
(ii) Daya Ram Sahni found a number of seals near the ruins of Harappa. The importance of seals to be realised.
(iii) New excavations took place. It was led by R.D Banerji. He found similar seals at Mohenjodaro. It led to the conjecture that these sites were the part of single archaeological culture.
(iv) All artefacts, (seals, toys, pottery) from the same unit were grouped whether they were found at different stratigraphic layer. Based on these findings in 1924 John Marshall announced the discovery of a new civilisation the Indus valley to the world.