Carnival says it will expand its use of exhaust gas cleaning systems as part of a $400m investment to meet pending rules that will limit shipping's sulphur emissions.

The world's largest cruise ship operator says it has installed exhaust gas cleaning systems, otherwise known as scrubbers, on 60 vessels so far. As reported in TradeWinds, the company has set a goal of installing scrubbers on some 70 ships by the end of this year.