An Indian resident travelling abroad can buy up to USD 3,000 equivalent in foreign currency notes per trip. Anything more for the same trip goes on a prepaid forex card or as a bank transfer.
The yearly limit
All the foreign exchange an individual buys or sends in a financial year — notes, cards, transfers, overseas tour packages — counts towards the Liberalised Remittance Scheme limit of USD 2,50,000, across every bank and money changer.
Indian rupees
You may also carry up to ₹25,000 in Indian currency when leaving India (higher limits apply for some neighbouring countries — check before you travel).
Coming back
Returning travellers can keep up to USD 2,000 in foreign currency notes for future trips. If you bring in more than USD 5,000 in notes, or USD 10,000 in notes and travellers' cheques together, declare it to customs on the Currency Declaration Form — you will need that form to sell the notes in India.
Nepal and Bhutan
Foreign exchange is not released for travel to Nepal or Bhutan; Indian rupees are used there.