How reliable is the information of periplus?

The "Periplus of the Erythraean Sea," a 1st-century Greek navigational text, is generally considered a valuable historical source for understanding ancient trade routes and commerce in the Indian ocean. However, its reliability can vary; while it provides detailed descriptions of ports and trade goods, it reflects the author's perspective and may contain inaccuracies or exaggerations. Additionally, the information may be influenced by the author's experiences and the prevailing knowledge of the time. Thus, while useful, it should be cross-referenced with other historical sources for a more comprehensive understanding.