What I said was that it will gradually have a major impact if the the Chinese could sustain it. The Chinese would not have done this unless they were ready for it - they say that they are. They are the second biggest economy in the world and when they make such an announcement, it needs to be taken seriously.
Currently, there are two major oil exchanges in the world, one in the US and the other in the UK, where the oil is bought and sold in mostly dollars. If these exchanges may also start floating RMB for oil sale purchase, it will bring in a change. If as a next step, the Chinese float their own oil exchange and lets say the Russians also do that, an alternative arises, with serious implications. Incidently, the Iranians also have a small oil exchange but could not establish it in a manner due to probable ramifications from the US.
India buying and giving rice or wheat is BS at the world level.