1. Archaeological finds mention that Harappan civilisation had contacts with distant lands. Its reasons was exchange of goods. 

2. Copper was brought from Oman. Omani copper and Harappan artefacts, both have traces of nickel. A distinctive type of vessel coated with thick layer of black clay, had been found at Omani sites. 

3. These vessels with coating used to prevent the percolation of liquids. Probably Harappan people exchanged the contain of these vessels for Omani copper. 

4. Mesopotamian texts mentioned contacts with Dilmun (Today Bahrain) from where copper was procured. Copper products excavated from the sites of Mesopotamia have traces of nickel. 

5. Many archaeological evidences indicate towards the distant contacts, seals, weight, beads etc of Harappan culture. 

6. The texts of Mesopotamia mentioned the regions-Dilmun (today Bahrain), Magan and Meluhha. They explain the products from Meluhha. 

7. The products were like lapis lazuli, camelian, gold, copper. 

8. Oman was connected through sea. Mesopotamian texts refer Meluhha as a land of sea. Depictions of ships and boats on seals have also been found.