I know this question is really old but I'm going to answer it. The Indus river valley civilization is located where now western India and Pakistan are. Today Pakistan holds around 220,892,340 people, and western India holds 173,343,821 people. Therefore, you can say that the Indus River Valley holds around 394236161 today. Idk if I'm really correct but I'm doing a project with this, and this was my answer to the population today part, hopefully, this helps anyone who needs it!
