(Updates with key environmental session being postponed)
LONDON, March 12 (Reuters) - The International Maritime Organization (IMO), the United Nations' shipping agency, has closed its headquarters in London and postponed a session of its Marine Environment Protection Committee (MEPC).
The IMO said the moves followed an assessment on Wednesday by the World Health Organization, which said the virus can be characterised as a pandemic. It added that IMO staff were working from home where possible.
The key MEPC committee was meant to have convened on March 30-April 3 to discuss measures to cut carbon emissions from shipping.
The IMO has already postponed other meetings in March due to the virus.
Global shipping accounts for 2.2% of the world's CO2 emissions, and the industry is under pressure to reduce those and other pollution. About 90% of world trade is transported by sea. (Reporting by Jonathan Saul; Editing by Jan Harvey and Kevin Liffey)