Hello there, I am a studying historian, one of my areas of interest is Pre-Islamic Iran, all the Iranian dynasties and realms like Elamites, Medians, Achaemenids, Parthians, and Sassanids all have a very interesting history. Pre-Islamic Iran has a unique history of tolerance amongst many other civilizations of antiquity. The Achaemenids had a very interesting style of rule, based around satrapies, the Iranians rulers also often allowed native rulers, of lands they conquered, to govern their own lands as long as they paid tribute to the Shahanshah, the king of kings. The Persian kings ruled a vast realm, and thus giving autonomy to some regions and dividing governance into satrapies helped them manage administration. The Persian lands around the Indus Valley, Punjab, and in that region were no exception. Although compared to the Greeks and Kushans there was not as much permanent settlement of Persians into the region, they helped expand trade and contact between the subcontinent and the civilizations to the West. India and China, were regions that were isolated, their civilizations developed in isolation, the Chinese developed along the Yellow River, the Indians around the India river. They didn’t leave behind much in the way of excavations though, some sites potentially linked to them, but not much. The Persian Achaemenids divided this region into 3 provinces, Gandara, Thatagus, and Hindush (Magee, et. al 711). These lands were conquered by Cyrus the Great in his military campaigns, Cyrus sacked and destroyed some of the cities in the area, but his destruction doesn’t at all compare to that of other conquerors. In the capital at Perspolis, there was a relief on the hall of one hundred columns depicting the Indian people, bringing gifts and tribute to the Persian King (Magee, et. al 713). I suggest you read this article for more information https://www.jstor.org/stable/40025695?seq=11#metadata_info_tab_contents