"Developed" vs "Developing" are vague moving standards in development economics. The US and other western nations have developed considerable more since these terms came into use. It seems like they basically just mean a western standard of living vs significantly less than that.

With how the terms are used, India is probably very far from becoming a developed nation. However, India could certainly reach the level of prosperity enjoyed by western nations at the time they were first considered "developed".

Additionally, I expect to see particular cities reach a "developed" level at some point. Most likely that will be major ports of trade.