It's written in the first two paragraphs of the article:

The 2022 explosion and leak of the Nord Stream pipeline in the Baltic Sea resulted in the release of 485,000 tonnes of methane into the atmosphere, according to a new study of the disaster.

The methane released from the pipeline was the largest human-caused methane emissions event in history. But the magnitude of the release is twice as bad as previously thought, according to a new study conducted by the United Nations Environment Programme and published in Nature. Prior studies estimated the methane released from the disaster at between 75,000 and 230,000 tonnes.