Shipping and green groups have united in a call to ban the transport of non-compliant bunker fuels.
They want the prohibition to enter force along with the 0.5% sulphur cap in 2020.
From 1 January of that year, the IMO is reducing the maximum permitted sulphur content from 3.5%.
"Unless a ship is using an approved equivalent compliance method, there should be no reason for it to be carrying non-compliant fuels for combustion on board," the organisations said in a joint statement.
