The Reserve Bank of India (RBI) wants refiners to restrict dollar buying to $500 million a week to clear their oil dues to Iran in order to avoid downward pressure on the rupee currency, three sources with knowledge of the matter said.

Refiners that owed about $6.5 billion to Iran have so far cleared $770 million in euros for Iran through Turkey`s Halkbank. The state-run Union Bank of India (UBI) facilitated the payments to National Iranian Oil Co (NIOC).