Even though China formally started exporting it only after 119 BCE, silk, dated to much earlier period, has been found in Germany, Egypt, Mediterranean, and Central Asia. This silk, it was explained, came through contact with the Chinese. Now there is a new explanation: sericulture was known to other civilizations and a new paper reveals that the Indus people definitely knew about it.
The new evidence which comes from Harappa and Chanhu-daro show silk threads almost a millennium earlier than previously believed; the earliest find for silk in India was a thread found in Nevasa (1500 BCE). Now three silk fragments, which came from wild silk moth species, dated to the mature Harappan period (2600 – 1700 BCE) show that wild silk was used not just in China.
Previously it was believed that silk and the associated technologies — removing gum from silk and collecting silk strands on to a bobbin — were known only to the Chinese, but now we know that the Indus people too knew about it around the same time. The Chinese knew about silk weaving from 1600 BCE and had silk textiles a millennium back; the Indus discoveries are only few fragments used to connect copper-alloy bangles.
So for all the years of Mature Harappan, we have only three strands of silk. Does this mean that silk was not so important there or that it was not preserved well in the region or that the archaeologists were not trained to look for it specifically.? This finding, hopefully, is the beginning of new discoveries which will answer all those questions.
Reference: New Evidence for Silk in the Indus Valley