There is no limit to bring foreign exchange in India from the US. However, the aggregate value of foreign currency notes in excess of USD 5000 or equivalent and the aggregate value of foreign exchange in the form of currency notes, bank notes or traveller’s cheques in excess of USD 10,000 or its equivalent must be declared to the customs. The limit for foreign currency notes is USD 3,000 and must be declare by filing CDF (Currency Declaration Form) if it exceeds the limit .Bringing INR from abroad is prohibited in India. But Indian residents can bring upto INR 25,000 per person.
At this point in time, there is no clear directions as to how overseas Indian and residents can exchange the Rs. 500 & Rs. 1000 notes. Please see this link:https://www.compareremit.com/money-transfer-faqs/how-indias-currency-withdrawal-of-rs-500-rs1000-will-affect-nris-0806/