Because of the geographical position (India is between China and West Asia and Europe) India always was icluded and made money from trade.
India traded cotton, silks, dyes, drugs, gold, ivory, often earning great fortunes. From Middle East & Roman Empire, they brought back pottery, wine, metals, some slaves, and especially gold;
Indian traders were selling West Asian glass and wool to people in China, and Chinese things like silk and pottery to people in West Asia.
