1. The contract, for the 380-centistoke grade or bunker fuel, with a size of 100 metric tonnes each, will be traded on a free-on-board (FOB) basis, the exchange said.

2. IMF and World Bank studies show a carbon-based bunker fuel tax, for example, could raise $30 billion annually by 2020.

3. Most ships run on bunker fuel, which is cheaper than distillate, but more polluting.

4. Because of this, the hydrocarbons in gasoline, diesel, bunker fuel etc. , do not burn completely.

5. Up to that time coal was chiefly used as a domestic fuel but from 1812 onwards it went to sea as bunker fuel.

6. And they could have moved to bring the huge, dirty market in bunker fuel for shipping and aviation, hitherto excluded from discussion of caps, into the negotiations.